If you have read that Purpur is the "most configurable" Minecraft server software and are wondering whether to start there instead of plain Paper, it helps to understand what "configurable" actually means in practice before deciding.
Purpur's pitch: gameplay you can tune without a plugin
Purpur's whole premise is that a huge number of small gameplay behaviors people normally reach for a plugin to change, mob AI quirks, whether certain mobs can be ridden, specific block or entity mechanics, should just be a config toggle instead. Its config files read like a long list of "can this be different" questions, each with its own on/off switch or numeric value. If you have a specific vanilla behavior you have always wanted to adjust, it is worth checking Purpur's config before assuming you need a plugin for it.
It's still Paper underneath
This is the part people sometimes miss: Purpur does not compete with Paper's performance work, it inherits it directly and builds its extra features on top. Choosing Purpur is not a tradeoff between "fast" and "customizable", you get Paper's async chunk loading and optimizations either way. The actual decision is purely about whether you want the extra configuration surface.
The tradeoff: a smaller, newer project
Purpur has a smaller maintainer and contributor base than Paper, which is by far the most widely used and most heavily tested server software in the plugin ecosystem. In practice this means edge-case bugs may take longer to get fixed on Purpur than the same bug would on Paper, and there is less community documentation specifically written for Purpur's quirks versus Paper's. None of this affects plugin compatibility, which stays identical, it is purely about how battle-tested the jar itself is.
When Purpur is the right starting point
Choose Purpur if you already know you want to tune gameplay mechanics beyond what plugins and Paper's own settings expose, and you are comfortable being on a slightly less mainstream jar than Paper. If you are setting up your very first server and are not sure yet what you want to customize, starting on plain Paper and switching to Purpur later, once you actually hit a specific setting you wish existed, is a perfectly reasonable path too, since the switch is non-destructive to your world and plugins.
Try both without committing
Because Purpur and Paper share the same plugin API and world format, moving between them is just a version change, not a migration. Tick Hosting's panel lets you switch from the dashboard in a couple of clicks on any plan, including the free tier, so you can compare Purpur's settings against plain Paper on your own world before deciding. Get started on Tick Hosting's plans page.