Sounds like you should have your 26" cut, crowned and threaded @20" and call it a day. Unless it's a carbon that can't be cut down, then if it's a custom action, just have a .200"-.220"ish freebore 30 nosler prefit made for it.
On the other hand, I will never detour an American from getting another rifle. On a tikka action, it makes it a little harder for your goals. Rich's mega will get about everything possible from that action, and would be about the minimum I would consider for a dedicated 1000+ elk rifle.
However, my wife's rifle is a 20" 7 max, just an improved saum. It's best node in a 650 yard ladder was the 170 PVA Cayugas at 2835, a fair margin under max. 1000 yards at my home elevation of 6,300 ft, gives 1925 fps and 1400 ft-lbs @ impact. The areas we hunt elk at 7500-10,000 ft elevation, a lot more, I wouldn't hesitate to take an elk at 1000 in the right conditions. And I didn't, 2021 season I used it to dump a big cow at 1035.
I built this rifle for my wife with some compromises, I wanted recoil of the 9.5 lb rifle to be soft while supressed, so that kind of limited me to 7mm. As you know, the 20" supressed rifle I built for myself was a 30 nosler, I dont really mind some recoil. A 208 lrht @2935 is an easy 1000+ elk rifle, especially at higher elevation.
Good luck with your decision, just make sure and update us what you do!