So here i own and run 5 servers. They all very from mod count but our most is 66 mods on our Deer Isle Server. Have Zero Problems. i have seen running way to many script mods will cause a crash. Its all about which mods you use but i can say you need to pick which mods you use wisely if you dont then you end up in this boat. Ive used the same mods since 1.13 and still Zero problems as long as the mod as been updated to meet that new 1.15 update. Ive been hosting since the beginning of the year. only ran into a hand full of mod you really dont want to use.