Paper, Fabric and Forge solve different problems. Picking the wrong one is the most common reason a server feels slow.
Paper — plugins and raw throughput
If you want a vanilla-plus survival or minigame server driven by plugins, Paper wins on performance and stability. It won't run mods.
Fabric & Forge — mods
For modpacks, your choice is made for you by the pack. Fabric is lighter and boots faster; Forge has the deeper mod ecosystem for big kitchen-sink packs.