A few years ago, Old School Runescape released a new gamemode: deadman mode, where pvp was enabled for the entire world, minus a few safe zones. Whoever killed you would get to keep whatever you had on you, (plus several items in your bank, but that's not really applicable to this game,) and you would lose well over half of your stats. The reason people stuck with it is because xp rates were raised drastically from the base game, meaning building accounts was much faster, and deaths weren't as devastating. XP rates alone weren't enough to keep many players hooked, though, so after a few weeks/months after the new season of deadman mode when the servers reset, there were only a handful of players online. With the most recent season, they introduced two aspects that kept the players online for much longer: daily xp limits and catch-up rates.
Depending on how long the season was running for, players could only gain a certain amount of experience, shared among their combat-related skills. For instance, they could earn up to 1 million experience between all of their skills on the first day, 2 million on the second, and so on. If players joined 3 days into the season, they could still reach 3 million xp despite having a late start. This meant that the players who could play the game 24/7 could still progress, and still had incentive to, while the more casual players could still get to the same level. They also introduced a mechanic where, if the player died, they would have a large modifier to their xp gain until they reached their original stats. The season that implemented these changes kept players hooked for much longer, and every season since has kept this change.
What I would propose is the same kind of system, where your characters are limited to an ever-increasing cap depending on how long the server's been running for. Something like 100/200 stats per week would still keep high-end players striving to be the best, but still let slower players get to the same kind of level. Also, when you inevitably die, I would propose a temporary increase to your character development rate, but rather than giving you a boost until you get back to your original stats, the boost would last until closer to 80-90% of your original stats, possibly dependent on how your ancestor's remains were handled.