I'm feel you, OP. I've had a few Tikkas over the years. Early ones (circa 2006-2010, mostly 308s and a 270WSM) shot great, all of them. Have had 4 since then (3 x 30-06, and one 7mm-08), have not been that great. To be fair, 1.5 to 1.7 ish MOA guns for 10 shot groups, with ammo they likes, but also to be fair 2 or 3 MOA with ammo they don't. Def not like the earlier ones I had that would tack drive nearly whatever I fed them.
i have a 7mm-08 currently that will run 1.5 MOA with ammo it likes for 10 shots, but have never got it under that. 5 or 6 bullets and 4 or 5 powders, all about the same
If I was a 3 shot group guy, it's shot a bunch of decent 3 shot groups. But by 5 to 7, the truth starts to show.
YMMV, but I haven't bought new Tikka that made me happy in nearly 20 years.