With Silver at UA you don't get access to Economy Plus seats until at check-in. Is that good enough for you? If not, that could be a one-step answer to your question!

Also, you want to reduce fees. Go check the elite status information and see what the differences are in fees at each of these airlines between first and second level of status. First level of status doesn't tend to get much waived in the fees that you care about, but I'm not even sure how much second level of status gets in waived fees.

But also do the math on fees. If you're only going to incur the fees once or twice a year, but you have to pay more than those fees to earn the status (remember, at each of these two airlines there's not only a minimum number of qualifying miles for status but also a minimum amount of qualifying spend. if not this second by the start of next year), is it worth it to avoid the fees?

At most airlines (but again I don't know all the specifics of DL), first-level status mostly gets you just the benefits you said you don't care about (free checked bag, priority boarding, etc), ie, not much different in kind (though sometimes better in quantity*) than what you typically get as benefits with that airline's credit card. You typically need second-level up to get much different benefits than just what the airline's credit card gives.

*By "quantity", I mean first-level status may get more free checked bags than just credit card holder, first level status may board one group earlier than just credit card holder, etc.