I used #WordPress to upload my #Mastodon posts (and my https://davidbisset.social site syncs with it fine). I cache 50k posts and works great.
If you aren't a WP user (and want to go static 100%) then @richard@richard.social post might be of interest.
"Creating a static Mastodon user’s archive"
https://ricard.dev/creating-a-static-mastodon-users-archive/