Unless you find the card useful as-is, I would close it. It will not hurt your account age because it will stay on your reports for ~10 years. Due to the length before unsecuring and the inconsistency of what we anecdotally see in the timing of when or whether it unsecures, I think the idea of unsecuring should be disregarded with this card. By the time it does unsecure, if it ever does, you will have long since been able to get a better unsecured card. Example: this was my very first card in this stage of y life when I started by build/rebuild in spring 2019. I closed it months later, and one year later, I opened two Citi rewards cards with credit limits around $10K each. JMO.
Anecdotes are all over the map. I think the fastest graduation I have seen mentioned here is 11 months. It is common for it to take about 2 1/2 years, and some people seem to wait forever.
It is a good secured card IMO, just not one I'd count on graduating in time to be helpful.
Without knowing more about your profile, I wonder if you can qualify for some unsecured cards, such as Amex Delta blue or Amex Hilton card. Amex has a pretty reliable prequalification feature. But in terms of secured cards that graduate, Discover is #1. I'd also look at TD Bank if you live in a state with that bank, and Navy Federal if you are eligible. Edited to add, yeah, if you're going for a mortgage, that should take priority over card applications. Maybe just let it ride in case it does graduate. If not, close and replace AFTER the mortgage. JMO, good luck!