Giacomo M,
Assuming the Connect you have is S2 compatible, see this link:
https://support.sonos.com/s/article/4786
...then you will be fine to use the Sonos Arc and Sub (Gen3) within the same Household, otherwise you will need to run them in separate households. The Sonos Beam and earlie versions of the sub will run within either an S1 or S2 Household. The Sonos Boost (not a Bridge) will work with either system too.
Your turntable with pre-amp will be able to connect via the ‘Connect’ line-in and is able to play on the Beam or Arc (bonded to the sub) providing the ‘Connect’ is capable of being setup in the same Household. So the important bit here, is to check the compatibility of your existing Sonos ‘Connect’ device.
if you go to your Sonos account profile online here:
https://www.sonos.com/myaccount/user/profile/
...and select your ‘System’ tab it should (hopefully) mention if your Connect is S1 compatible only… so, if you can use either S1/S2 system then you should be fine to choose whatever additional Sonos hardware you prefer.
Hope that assists.