LTE with carrier aggregation gives better speeds than normal LTE. also, band 5 has more stability (though lesser peak speeds) than band 40. I am using Jio SIM with TP-Link MR600 which is giving min 40 mbps speed and peak speed upto 90 mbps on 2CA (keeps switching between 3+40 and 5+40)4G can never match the stability and speed reliability of DSL connection, Fibre is even better. I have already used JIo , the speed is not that great and fluctuates a lot and that is common in wireless networks......
I don't know about Hathway. There used to be many leaflets with phone numbers stuck to electricity posts in Beckbagan More. But that's far from where you stay. Call their number on the website. Contact your neighbors and get reviews about ISPs there. Their services depend on location, be it alliance, Siti, Wishnet, or Airtel.How about Hathway broadband ?