I agree that theres a risk of picking it up from a vaccinated or unvaccinated person but probably more risk from the unvaccinated one here 'cos of there job. It may depend on why there unvaxxed. if there someone who believes covid dont matter and takes no precautions like distancing then I'd avoid them. But some who are nt vaxxed by choice or as they cant have it will make up for it by being extra cautious, regular sanitising, mask, distancing, avoiding crowds, so they be less risky.
I agree with LFTs, we did them for a family get together, just asked and took people at there word but everyone felt that bit more safe. Of course the kissing has to be minimised and windows need to be open.
But also ask your doctor, they might say any close gathering that lasts 30 minuits or more is to risky given your condition