Semien has also been a top 5 WAR player in the entire league for the last two 162 game seasons. His 2020 season after the first 2 weeks or so resembled this type of player as well, except the season was too short for the overall numbers to look the part. There will be decline in his 30's, but if you wanted a safer bet to be worth the deal he's going to get, then Semien > Ray, IMO. The last start against the Yankees by Ray is kind of warning sign. A little dip in velocity or his command suddenly getting lost again, and he could be an albatross very quickly. Even with an offensive decline, Semien should still have the higher floor, and he clearly has the higher ceiling.
I don't get Kawhi vibes with Semien either. Maybe he does prefer the West Coast, or a chance to play SS again, but I feel like he legitimately likes the team and would re-sign if the offer was the highest. Whether the Jays should give him a Springer contract is the question. You can't have too many of those because it might restrict available resources for extensions to young players. If they give Semien something like 5/125, then I'd probably avoid another big FA deal for a while, and try to get by with shorter term deals elsewhere.