Im looking for suggestions on whether to start in f open or f-t/r
Planning on shooting mainly at 1000 yards
I do not have a mentor
I reload but do not currently anneal or turn necks
Budget : id like to try to keep it under 2000 in upgrades to one of my rifles i already own rem 700 or a savage model 10
Like many specialty sports, you don't know enough when you're just starting out to know what you don't know. Participate in half a dozen events and you'll learn more than you can imagine; therefore, purchasing your "dream" equipment on day one is foolish. That goes for target shooting, car racing, computer stuff, sexual experimentation with the opposite sex, and lots of other sports.
You'll need a couple of things to get started. A rifle with a rest for F-open or a bi-pod for F/TR. The stuff you own will do just fine to begin with. Don't show up until you can shoot a 1/2 MOA five-shot group at 100 yards and until you know how to work a ballistic app well enough to figure out how to adjust you scope to go from a 100 yard zero to a 600 yd zero (or whatever range your club uses). When you can do that, don't wait any longer. Find a local F-class match and go for it. If you don't have a shooting mat, bring an old quilt. Don't expect to win, but expect to have a lot of fun and meet some nice people.
Depending on your eyesight, you may or may not need a fancy scope. I'm older than dirt and going blind in my shooting eye, so I use a medium priced 50 power scope. But if your eyes are good, chances are a scope you already own will be OK to start. Can you see a golf ball at 600 yards or a tennis ball at 1000 yards? If so, you're OK to begin with.
You say you prefer 1000 yards, but you are likely to find more events will be held at ranges of 600 yards.
Anyway, once you're barely capable, load up 80 rounds of your best stuff and get out there. Show up a little early, find a friendly shooter, admit you're clueless about F-class but that you're an experienced shooter, and see if he will take you under his wing. Chances are he will or someone will. Once you get your sea legs, ask to look through various fancy scopes to see how you like them. Unfortunately, the expensive ones are better, but you already know that. Ask about rests, bipods, rear bags, stocks, actions, barrels, bullets, powder, and all the other stuff you can spend your money on. Keep shooting with the equipment you already own until you know what you really want/need.
Now for the bad news. Unlike some sports, you can't buy yourself a first place finish by spending a ton of money on equipment. Once you can shoot 1/2 MOA at 100 yards, you will need to learn how to read the wind before better equipment will help very much. They say "F-Class is all about the wind"............... sad to say, that is all too true.