What are the options for the longest stay in Thailand on a tourist visa or with a non-immigrant O visa?

Hey folks. Hoping for advice on options for the longest possible stay in Thailand. I have the option of either tourist visas or the non-immigrant o visa through marriage and own property in Thailand. I will be applying in the U.K, although it all seems to be online now?

I did a quick search through past posts and saw that 3-months on an o visa then a 2-month extension is an option? (I’m not fussed for the whole 400,000 in a local bank option after that). What would be the longest for tourist visas?

I more or less lived in Thailand both on ‘o’ visas (1-year multi) but found tourist visas to be the better option given I travelled a lot. Ideally I’d be jumping borders on tourist visas but can’t see this being an option for a while now without quarantine? Is there any rumours on when things may open up properly again?

Was back in the UK for a wedding when this whole covid stuff came about and have been stuck here since. Managed to sort the Mrs UK settlement/residency so at least we are comfortable but I will probably go mental if I’m here much longer. Guessing it will be 5-months Thailand then 7-months UK each year at best until this is all over.