hello, sorry for the late reply. i was on vacation.
Coming to the point, i highly recommend you to go with SiForum https://github.com/sinanisler/SiForum
what else do we need? Full CF APO support for just $5 … host somewhere and use CF apo to boost the experience. no need to worry about Redis or the server. in my case, i am hosting with digital ocean + free Plesk panel believe it or not till today i have not touched the server running successfully for the last few months.
this developer (one of the core dev of siForum) helped me to migrate my data from flarum to WordPress. i was happy with his work and i paid energy exchange charges for migration.
SiForum was designed keeping SEO things in mind
if you are a dev you can look into this code and write your own migration script https://github.com/serkanalgur/flarum-to-wordpress
i have tried all the WordPress QA scripts like bbpress QA press …etc but it is a rabbit hole and you had to stick to it forever. remember they maintain your questions and answers separately as posts and project them as one page which i am not a big fan of.
just use SiForum theme or any other simple theme with WpDiscuzz.
i have over 20k users with 300k posts … all i needed is good SEO support.
Discuss or flarum they really do not give much importance to the SEO i can say they are application minded … these softwares are only useful when you have user base like Reddit. in my case like i told you all i needed was a good web presence and good SEO.
Feedback about other scripts which you have mentioned
why URL structure is weird? (that is the reason i do not like all WordPress qa scripts)
i want all URLs to be like this https://domain.com/usb-C-iphone/