I would suggest looking at different tyre brands or models. I have been running tubeless (on road) for about the past 3 years...varying between 30mm and 42mm (gravel bike, but running basically slick tyres).

Different tyres have different wall constructions, and so some can leak a lot of air. I find that after I put on a new tyre, they leak air for the first couple days, but it's greatly benefited by going for a few rides (the extra pressure gets the sealant into all the nooks and crannies of the tyre casing, filling the gaps), and then maybe lose a PSI or two per week (when I run at 50psi).

I change sealant about every 6 months, just because it dries up. Not particularly due to fluid leakage.