For me it’s more noticeable when I pick up an older device and it seems less smooth. Otherwise I feel that’s not enough to upgrade for as some claim to not notice at all.

That or the device’s connected to any services like Microsoft 365 or some managed service.

I’m in exactly the same position and have gone with keeping my work and personal phone separate. Having work stuff on your personal phone leaves you open to error and it’s more difficult to switch off, even with focus modes. When I’ve had similar situations I’ve took the risk and just used the phone of choice (as I have a spare phone that tends to be a better spec and I prefer to use iOS for the automation) and have never been pulled up but, if your company are on top of their security accreditations then they might be checking for unauthorised devices. It’s sometimes reassuring to see if anyone else has been getting away with it.