[Edit: Specific to Jio 4g and 5g network in India]
After the update to stable Nothing os 3 on Phone 2a, there are significant network drops when trying to connect to Jio 5g or 4g. Turning off smart 5g does not help much, the phone fails to connect or takes a long time to connect. And frequently disconnects completely when inactive or waking up from standby. Calls and data simply stop working.
This may be related to mediatek drivers(?)as I faced a similar issue with another phone manufacturer after their November update. The problem got solved on that phone with bug fixes for Jio network issued by the manufacturer.
I hope other users who are facing this issue can report their experiences in this thread and Nothing can issue a quick fix.