Changing to new phone and changing plan

[tashedelek]

I've bought an unlocked moto g stylus 5g 2022 to replace my current moto g stylus 2020 (also unlocked). I'm just replacing the phone, not adding a new phone. And I have some questions:
-- Do I need a new sim card for the new phone because the new phone is 5g, or can I just move the sim card from my current phone? The current phone is 4g LTE.
-- I intend to change my current TracFone plan to a 1 year unlimited 5g plan. Is it Ok to do that while I'm still using my current 4g LTE phone or should I wait for the new 5g phone?

Thanks for any help and feedback...