What will happen if I use 33W charger in 10W phone ?

No offense meant buddy✌🏻 I would prefer to err on the side of caution & not be too trusting wth the circuitry in phones or chargers for 2 reasons.
One is even if things are in tip top quality, things wear out.
Two Different companies use different types of circuitry, I am not too sure they are all compatible with each other.
And I always remember that a Li ion battery is a potential fire hazard.
Also though there are standards to be followed I am not too sanguine about whether they are followed by all & whether there are checks by any institution that standards are followed.

Google today require all androids to be compliant with USB PD spec. Recent phones should be fine as a result. Of course, things can go wrong.

Thinking about it though, I don't think I'd ever put anything other than standard Mi charger on my Note 5 if I can help it. Not when it's my only phone 😅. If I am in an emergency or if I can afford another phone easily then yeah, but I'd still go back to using the manufacturer one.

@mahadevan_iyer if you can,you can buy a replacement adapter from Xiaomi. It costs around 300-400 I think for the 5V2A. Think of it as insurance xD.

Since it's your old secondary phone, and If you think it isn't worth the 400 rupees investment then you can use the Poco one, both are from the same manufacturer, should be fine.

The way we treat our electronics change according to how easily we can replace them.

Phone will charge as per it's charging rating. No issue. I have been using 65W USB C brick for my phone and laptop without any issue for last 12 months

As to how things are unpredictable 2 Asus max pro M1 & 1 max pro M2 suddenly got swollen battery during the current lockdown. Always used company chargers, no games played on any of them & never kept on charge overnight. The 2 M1's we could flog as ecommerce sites opened up fr my area but not the service centers. The M2 just recd it battery last week though it went bad in April. Net result 3 new phones.
The M2 was 13 months old when problems started & the M1's were 17 & 19 months old.

Oh the zenphone max pro series issues are well documented already. 😅 My friend has one, it got swollen, his friend bought one, it got swollen. You can search on YouTube, it's a wide spread issue.

I can't seem to find those old videos, but here's a thread with people complaining Zenfone max pro m1 back bulge and strange smell

Considering that they sold over a million M1/M2 phones, it's a big shock to the customers as this was never really addressed. I have spoken to senior people in that organization & I am not impressed at all. & they promised replacements for M2 users whose phone got stuck in boot loop but almost none got that. Ask @krish_88 . And they have got away with it.

Not to mention the never ending pie beta which is still buggy af, my stock android fanboy friend is now running miui of all things in his m1. They all failed around the same time as well, during lockdown.

And I am using a Samsung M31😔

socrates said:

Considering that they sold over a million M1/M2 phones, it's a big shock to the customers as this was never really addressed. I have spoken to senior people in that organization & I am not impressed at all. & they promised replacements for M2 users whose phone got stuck in boot loop but almost none got that. Ask @krish_88 . And they have got away with it.

Click to expand...

Their last update screwed up my device. Luckily i had a backup. They seem to very ignorant and never acknowledge the issue.. Yes, There have been reports of ppl getting the promised replacements... This hasnt happened in my case. I have decided not to take chances with Asus in the near future.

socrates said:

For anyone who thinks that only voltage matters & not the amperage, I would like to say only one thing. A automobile spark plug cable carries anywhere from 15 to 25 kilo volts but ppl who feel it (including yours truly) live to tell the tale only because the amperage is v v low. If it was higher I wouldn't be typing this.😁😁

Click to expand...

No offense but you might be confusing things here, no one is saying amperage does not matter, but what we are saying is that the current pulled by a circuit depends upon its resistance and potential.

V=I*R should be enough to explain this
Given that V is constant and R is a function of temperature(T) and battery percentage(P), (obviously not as simple as that, length of wire etc also matters)
V=I*f(T, P), I (current) = V/f(T, P)
as f(T, P) is a function by definition (for set T x P x R, for each element combination t, p -> T x P, there exists a unique r -> R)

Notice that only one of the variable on right side of the 2nd equation depends upon the charger and that is potential difference, other variable is dependent on circuitry of the mobile.
You don't need to consider any internal resistance of the charger, as the voltage outside it is known (and hopefully constant given its a good quality charger)
therefore at any given battery percentage and temperature, I (current) will remain constant.

It is physically impossible to provide more current to a given circuit at a given electric potential difference by changing the charger.

Also, the lipo battery used inside most mobile phones can easily give max current of 50 A (generally much more than that, 100+ A), that's around 220w at full charge, if max amperage was a problem, your phone would already have been damaged.
Also the normal AC socket in you house can deliver max current of 10A (RMS) safely, does it mean that anything plugged into that socket will consume an average of 10A?

My post was basically to a comment that 'current does not matter'
And like I have said I prefer to err on the side of caution 😀
Are you sure that normal AC sockets deliver 10A? I always thought that our domestic electrical sockets come in 5A & 15A size🤔

Yep.... It was 5 or 15A until some years ago... when "Anchor" jumped and started putting up 10A instead of 5A....