The more likely issue for TUI at SOU is aircraft performance. Volotea can’t operate unrestricted with the 717 or the A319. Due to lack of alternative aircraft I’m not surprised it came to an end. Separately, the pax experience of a Q400 down to Spain is hardly ‘TUI product’. Doubt that will last either.
If this rumour of 220’s is true, they would be PERFECT for an airport like SOU.