as for the what solutions for bitcoin transaction fee
well implementing a new priority fee formulae that does a better job than the last one
here is one example - not perfect. but think about it
imagine that we decided its acceptable that people should have a way to get priority if they have a lean tx and signal that they only want to spend funds once a day. (reasonable expectation)
where if they want to spend more often costs rise, if they want bloated tx, costs rise..
which then allows those that just pay their rent once a month or buys groceries every couple days to be ok using onchain bitcoin.. and where the costs of trying to spam the network (every block) becomes expensive where by they would be better off using LN. (for things like faucet raiding/day trading every 1-10 minutes)
so lets think about a priority fee thats not about rich vs poor(like the old one was) but about reducing respend spam and bloat.
lets imagine we actually use the tx age combined with CLTV to signal the network that a user is willing to add some maturity time if their tx age is under a day, to signal they want it confirmed but allowing themselves to be locked out of spending for an average of 24 hours.(thats what CLTV does)
and where the bloat of the tx vs the blocksize has some impact too... rather than the old formulae with was more about the value of the tx
as you can see its not about tx value. its about bloat and age.
this way
those not wanting to spend more than once a day and dont bloat the blocks get preferential treatment onchain ($0.01).
if you are willing to wait a day but your taking up 1% of the blockspace. you pay more ($0.44)if you want to be a spammer spending every block. you pay the price($1.44)and if you want to be a total ass-hat and be both bloated and respending EVERY BLOCK you pay the ultimate price($63.72)note this is not perfect. but think about it