I have a rating of 2200, and I have similar difficulties with long calculations, but I have a good positional understanding.
My advice is:
- Reduce your blunder rate by making a simple check to see whether you hang any pieces, walk into mate etc. Check out What is the most effective way of reducing blunders?
- You don't need to calculate too far ahead. In my answer to How many steps can a grandmaster foresee?, I quote GM Soltis who argues that 2 1/2 moves ahead is fine for most positions
- Play quiet and solid openings that don't have many forcing moves or tricky tactics. Try 1.d4, the slav-defense or the caro-kann.
This is a correspondence game I played on chess.com recently. My play was quite simple all told. I stuck to looking a few moves ahead and stuck to a plan of targeting white's isolated d-pawn:
[FEN ""]
[White ""]
[Black "Bad_Bishop"]
1. e4 c6 2. c4 d5 3. cxd5 cxd5 4. exd5 Nf6 5. Bb5+ Nbd7 6. Nc3 a6 7. Ba4? {White is out of opening theory now. Now I can focus on recovering my pawn.} b5 8. Bb3 Nb6 9. Qf3 Bb7 10. Nge2 Nbxd5 11. O-O Nxc3 {My plan from now on is to reduce material and target white's isolated d-pawn. This is quite a straightforward plan that doesn't need much calculation.} 12. Qxc3 Rc8 13. Qd4? {White should keep queens on the board, especially when my king is still in the middle. If queens were kept on, then I might have to deal with some tricky long variations.} Qxd4 14. Nxd4 Rd8 {Now I need to double rooks on the d-file to put pressure on the pawn.} 15. Nf5 e6 16. Ne3 Bc5 17. Rd1 Rd7 18. Bc2 Ke7 19. b3 Rhd8 20. d3 Bd4 21. Rb1 Nd5 {I saw an opportunity to trade minor pieces, seeing as the c3 square is weak.[%draw full,c3,red][%draw arrow,d5,c3,green]} 22. Nxd5+ Rxd5 23. Bb2 b4 {I wanted to add one more attacker onto d3, by playing ...b4, ...a5 and ...Ba6.} 24. Bxd4 Rxd4 25. Re1 a5 26. Rbd1 Ba6 27. Re3 R8d5 {I wanted to make sure that white could not start targeting my pawns with Re5.} 28. f3 f5 {If I could scare away the rook, then the d3 pawn is more likely to fall. Also, having my pawns on dark squares means white's light square bishop has no targets.} 29. Kf2 f4 30. Re4 e5 31. Rxd4 Rxd4 32. Ke2 h6 33. Kd2 g5 34. Re1 Ke6 35. Re4 Kd5 36. Ke2? {Because the d3 pawn is now pinned, I can trade rooks and invade with my king.} Rxe4+ 37. fxe4+ Kd4 38. Kd2 g4 39. Bd1? {White now cracks and loses the d3 pawn, and next the e4 pawn.} Bxd3 40. Bxg4 Bxe4 0-1