I use a Vera Plus, but to be honest, I am thinking of switching to Homeseer. There's native Alexa capabilities, but I use the HABridge since I had that up prior to the Vera Skill. Based on your statements about SmartThings, I don't know that you'd like Vera. There are some others out there, like Hubitat, but I don't know much about them. May I ask why you left Homeseer?
I have used HomeSeer since its very early days, I was in fact one of their very first customers. When I first got HomeSeer it was pretty much just an X-10 based system.
It is honestly a really great system. Powerful, flexible, continually improving, and incredibly reliable. My Win7/HS has been running totally untouched for months at a time! It has, and has had for years, all types of capabilities that Siri/HomeKit and Echo/etc still do not have or come even close to.
I'm still running it on an obsolete Windows 7 computer, still using a now out-of-date version of HomeSeer.
Unfortunately most new ZWave switches require the neutral wire which my apartment does not have. I'm electrically illiterate so don't want to tackle playing around with that. Some of my current ZWave light switches are at the end of their life and either no longer work or have lost some of their functionality.
A few months ago I saw the "Kleverness" campaign on Kickstarter. Their switches do not require the neutral wire. I may well have made a big, very expensive, mistake here as there's been no news from Kleverness in ages.
Probably because of the obsolete version of HomeSeer I'm using I was not happy with its voice control, which I first started using many many years ago. I find Siri/HomeKit inadequate and slow. So far I like my Echo Plus and Echo with a couple of Lutron switches that don't require the neutral wire, and a couple of iHome plugs. I didn't find out about the Lutron switches until after I had committed to Kleverness/Kickstarter.
So, it was a question of buying a new computer with Win10, or HS hardware, upgrading to the latest HS-Pro software, and making compromises because of lack of neutral wire.
Or, going over to Kleverness switches, Amazon/Echo, and (probably) Wink for a much less powerful home automation set up but with much better voice control than Siri and, with Kleverness and Lutron/Caseta wall switches, no need for that cursed neutral wire.
There is definitely more of a learning curve to fully getting all it can offer from HomeSeer but, if you're prepared for it, certainly worth the effort. For me to fully upgrade my HS to the latest firmware, software, and hardware I'd almost have to relearn all about it as I haven't really gone into it for years; I'm in my mid-70's so guess I'm getting lazy and just want something simpler so am prepared to give up many of the great features of HS for a simpler life.