However, if you're prioritizing speed, it's recommended to connect the extender in wired mode. Verify if your extender has a LAN port for wired setup or consider configuring an old router as a wired extender.
Same 499 plan of BSNL FTTH
Bsnl always gives speed higher than the plan speed. Also you will get it on wifi too , where as the local other isp's constantly says speed test to be done when connected with LAN.