Nothing i'm afraid... If you don't have an already open lightning channel and you don't have any altcoins you can use, the only "real" sollution is to pay the large fee.
This is just about the most you could do. Apparently, these fees are the one means to sustenance for the bitcoin blockchain, it’s one means in which miners get the little or most they do and in times like this, we just have to bare with the trend. It’s a trend and it does goes out.
You might just pay the fees or perhaps, sort other means outside cryptos or Bitcoin payment. Perhaps you could even buy some altcoins (Stablecoins) preferably and use that to make your transactions. You would still arrive at the same means of paying without having high fees levied on your transaction. Only cause for worry would be the rate at which you would be offered the stablecoin or altcoins for sale. Nothing is real free my friend.
Bitcoin accelerators might be able to help as well.
Yes, unfortunately, our hands are tied are far as transactions goes, you can manually set the fees though depends on the user. Or just monitor the mempool when the fees is down or at least not 100 sat/vB++.
In my case though, transaction accelerators are very effective.
https://www.viabtc.com/tools/txacceleratorYou just really have to check it if there is a available open free slots as they usually filled in very fast.
By the order of submission, ViaBTC supports acceleration of 100 FREE transactions per hour.