My choice would definitely be to go with the larger Sonos Arc for that size of TV - I suspect the Beam will be quite small by comparison. Just swap the Playbar for the Sonos Arc and either use the Playbar elsewhere in the Home, or sell it on. Note your existing speakers are probably also eligible for trade-up/upgrade (if not previously used) so you can perhaps apply for discount vouchers on your Soundbar purchase and hang-onto/continue-to-use, your existing devices. See this link:

https://www.sonos.com/en-us/upgrade

However, if you do use the upgrade route and then sell-on any of your old devices, then don’t forget to tell the purchaser if you have used the upgrade voucher, so they know exactly what they are purchasing.

Hope that assists.