I see what you mean. There is a Bedrock Edition filter for mods, which leads me to believe PMC counts addons as just being mods for Bedrock. You should upload it as a mod.
At the top right above your username should be a button with an upload symbol that says "content". Click that, then "create new". It's pretty self explanatory after that.
For texture packs, you want to replace the ".zip" with ".mcpack" Then just open the file as if it were a word document or something and it should import to Minecraft.
.mcaddon files open directly into Minecraft. On desktop, double click. On mobile, just tap the file. It should open the game and import automatically from there.
You get xp for a lot of stuff, but I’d say the best way is to post good content. So far it looks to me like full game retextures for bedrock edition get a lot of downloads which will level you up a lot.
The only way I am aware of to recover something like that is to check through old screenshots for a set of coordinates. Really sorry if this doesn't help, I know what it's like to have that happen :(
