I don't know how authentic is the news about Mo Sallah leaving the club but regardless, having alternatives is very necessary and their defense needs serious attention too. I'm not trying to downgrade their current defenders but Vigil is not as strong as before and possible replacement should be in place in case of any misfortune. Arne slot seems to be satisfied with the present squad and will definitely figure out how he can get desired results with them.
I think the owner doesn't really like spending to be fair, can't say anything even if you have a great scouting team when your owner don't give you money to buy players. I honestly believe this is why they brought in Slot, so that they can use their young players more instead of buying players. Not sure what their target for next season is, but I don't think the owner aim for something as big as a quadruple charge or something similar. They really want to maximize profit as much as possible without hurting the team too much. Not sure if fans will like it tho.