Currently transactions with a tad under 140 satoshi/byte have been confirmed. See https://jochen-hoenicke.de/queue/ for a graphical representation.

But if you are unlucky and have an urgent transaction, there is no need to use the expensive or unreliable transaction accelerators, because Mycelium has its own transaction accelerator built-in. It uses the change of the original transaction with CPFP (Child Pays For Parent).

• Go to the TRANSACTIONS tab,
• tap to select the problem transaction, most likely the topmost one,
• tap the menu button or the three dots/squares in the top right,
• and tap the "Bump Fee (CPFP)" command.

Mycelium is better than most people think it is.