I assume that I will have to send as "priority"? I believe this is the highest fee I can do use this android wallet right?
The priority will not be enough, it will probably just check the total of the highest paying 1MB worth of transactions and adds a few sats on top, which won't be enough in your case, of course, it will speed up the stuck transaction by a lot, but don't expect to get 1-5 block confirmation. I have not used this wallet but they mention "Full control over fees" on their
website, which means if you dig a little you would find "custom" fees or something like that.
They promote it as full control over fee and they mention RBF and CPFP but used their wallet and RBF isn't even enabled
I'll take a look to see if a custom fee is possible and otherwise i'll just use priority and hope the transaction eventually goes through.