For target shooting, I would lean you towards the standard magnum cases - 7RM and 300WM. Both can be built into very accurate set ups. Brass is readily available and "cheap"... a whole lot less then some of the new gen super magnums. When I am target shooting, I don't want brass to be my limiting step.
Short magnums, except for the 300WSM, is pretty much dead and supply doesn't look very consistent going forward. And what is available is pricey.
Both the 7mm and 30cal have wonderful match bullets that make 1 mile very doable.... Not sure what your LR target shooting goal was but either will send slugs to 2000yds without much fuss.
Yes, they are slower then their largest cousins by maybe 100 to 200fps but when you want to shoot ELR, initial velocity really isn't that big a deal. EVERYTHING slows down and ELR accuracy really depends on how well that bullet was launched. If recoil and bore wear reduce consistency, all that happens is you miss at higher speeds.
Compare the same bullets going 100 and 200fps faster with any ballistics program. The actual difference in ELR ballistics isn't all that great. Typically, the faster will do the same thing 100 to 150yds further down range then the slower. If that is worth the increased cost and wear/tear, then go for it.
If you shoot far enough that your bullet will go subsonic, then another 100 or 150yds of transonic flight really isn't a big deal.
Last summer, I took my FTR rigs out to 1450yds... 308win with a big heavy bullet. Yes, drop was much more but putting bullets on target was really no big deal. The set up will hit a 5" circle at 1000yds in competition. I know the bullet will go subsonic so going further is now a function of elevation and leaning more into the wind.
Obviously, this is an extreme example BUT going fast at the start really doesn't mean as much as leaving ACCURATELY. My goal is to take the 308 to a mile this summer. There are many shooter who have already gone much further.
Enjoy your journey.... let me know if I can help with bits and parts.
Jerry