BetterEnderChest can disable the opening of the Ender Chest. Is it possible to give player negative permission in LP to not give player access to Ender Chest like in PEX? In PEX, I can simply add -betterenderchest.user.open and it would do the reverse effect but in LP is hard to figure out.

Any way unsetting the permission node betterenderchest.user.open (which is set by default).

Instead of /lp ... permission set <perm> or /lp ... permission set <perm> true, use /lp ... permission set <perm> false

Alternatively you can use the web editor. Just click on the green true to toggle it false.

Anyways. I’d recommend you reading the wiki. As that explains all of that. The recommended page to start is the Usage page.

Thank you again for helping!