As ABCbits says, if your redeem transaction is valid but only non-standard, you could try to submit your transaction via slipstream.mara.com. They say they accept non-standard transactions with other nodes won't relay and thus hardly can reach any miners mempool.

The Slipstream service might impose other restrictions to non-standard transactions and I haven't used it to submit non-standard transactions because I don't need to. You pay a higher fee rate than normal, but it's quite reasonable and especially now when mempool isn't much full at all.

It would be the goto method for me if I had a non-standard transaction or a transaction that I don't want to be seen in public until it is actually confirmed and mined into a block.