Periodically I'm getting a strong Burning smell (electrical or rubber) in the cabin of my 2023 Prime XSE under Regen in Hybrid mode. It's not on hills or under extreme braking conditions. What's also interesting is that the B Regen level switches from 2 - 1 on its own without me going into settings to change it...I had the dealership evaluate this but they couldn't find anything and couldn't recreate the smell while they had the car. At a loss....
Toyota Stealership will want error codes to take you seriously... A car that new shouldn't have this problem. But in general, a smell like this would indicate swapping out the battery pack with a replacement under warranty. But you'll need lots of proof to get that done without error codes. See how much data you can accumulate via OBD2 port and phone apps...
IMHO; that's normal 'off-gassing' of the new electronics and wiring as they get hot. The smell should dissipate over time. In the meantime, run your HVAC system on low from outside air so you don't end up gassing yourself. I've got 45K miles on mine and occasionally get that burnt electronics smell, when I run hard up or down the mountain. Your EV system is warrantied, if CT is a CARB state, it's 15 years or 150K miles. Otherwise it's 10 years or 100K miles. Make sure your traction battery fan inlets and filters are clear. Hope this helps.....
