Purchasing advice for SMB

I'll try to make this as brief as possible without leaving anything out. Looking to purchase some new equipment because we added a significant number of additional network jacks. Company has less than 100 employees, I'm the only IT person. Current setup...

Zyxel Zywall110 connected to AT&T 100 mbit fiber

Qty 2 Zyxel GS1910-48HP

Qty 1 Ubiquiti US-48-500w

Qty 4 Ubiquiti UAP-Pro

Qty 1 Ubiquiti UAP-AC-Pro

Qty 35 Yealink T46g Voip Phones on 3CX

Overall things work really well, all of the equipment has been installed for 4+ years minus the Ubiquiti switch which was a previous expansion. There are things I would love to have but don't currently. For example, even though the Zyxel's suppport VLANs, we aren't using them because those switches are a pain to configure in my opinion and 5 years ago when they were installed we were running Cisco phones and couldn't get VLANs to work with the phones even with Zyxel support. I would also love to have 10 gig between the two buildings using our existing fiber as my Hyper-V box has 10 gig in it as well.

I was pretty set on purchasing all new switches using the Ubiquiti Gen 2 switches that were just out of early access. That way I could gain inter-vlan routing along with the new VLANs with the understanding L3 wasn't available yet (And from what I read, maybe UBNT just removes that part later). After reading this subreddit and some other places I've been spooked on the whole idea.

My main problem is that the owner of the company loves to save every single penny we can on any kind of purchase. He loves that our current equipment cost so little even though there are key things that hold us back (like the Zywall110 being underpowered for the size of our network now).

Do you think with the size of the company that going Ubiquiti would really be that bad of an idea? Am I setting us up for failure later? After using the controller for a couple of years I've really grown to like it for seeing the devices on the 1 UBNT switch we do have and the configuration of the APs, I had hoped to have all my switching in 1 pane and when the UDM-Pro comes out of early access to upgrade the Zywall110 to that.

Any advice is really appreciated. I think I can swing a bit more in cost if it meant much better equipment, but having 1 pane would be awesome as well. Are there any other vendors that come close in pricing?

Edit - I realized I didn't give a total port count. I'm looking to replace all equipment and would need 1 48 port for the main accounting building where the MPOE is, 2 48 ports for the opposite building that's connected via SFP fiber right now (I don't know which type of fiber it is atm, trying to get that figured out), 1 24 or 48 port for the expansion building and I would also upgrade the base APs to Pro's (or all of them to HD's)