I don't see the problem with keeping Boruc as No1 for next season, with Travers as our "Cup Keeper" (depending on form they can obviously switch around if the need arises). Ramsdale can have a loan to a good Championship club, and we can just use one of the academy players like Dennis as third choice. If anyone gets injured we can always recall Ramsdale.
I really don't think we should be splashing the cash on a goalkeeper who may or may not even improve us; for me it's hardly a priority anyway, but if we were to sign someone I would much rather get a proven, experienced GK, instead of taking a punt on some kid.
IMO Ramsdale will be our No1 GK within the next few years and will probably be involved with England, and Travers has also emerged as a good prospect. I don't see how signing another GK of a similar age for big bucks is a good idea; doesn't send a particularly good message to our young keepers. That money would be better used elsewhere (e.g. Connor Roberts, or another CM).