Its not just range (distance from the lock to the next powered device in the mesh or the hub) its also the technology. A repeating device acts as a assistant for the relatively low powered lock, as @csteele talks about above.
A zwave plug/dimmer (sometimes called appliance module too) or light switch would also act as the forementioned repeater. Doesn't have to be a dedicated repeating-only device. 95% of powered zwave devices also act as repeaters (the exception being zwave bulbs.)
I don't have any experience with the aeotec devices. I'm sure on this forum you can find reviews. I would just plug in a zwave plug nearby as I have plenty of those laying around.
Another reason to pair it within 2 feet of the hub is when it pairs it uses a low power whisper for security during the pairing process. Once you're done pairing you can put it where you want. Put one beaming repeater as close as you can to the lock and one near hubitat and you'll be fine. I recommend the Ring v2 extender.
Hopfully my last question of the day. But my lock that already works. Should i be sending that to a beaming repeater too for better performance? Or should I just leave it as is because its working.
should I start with one repeater? Everyone keeps suggesting two. One near the hub the other near the lock. But it’s not that far of a distance. Should I start with one to save money or is there a necessary reason for two?
So I finally brought the hub close to the new lock and I was able to pair it just fine. So now both locks show up in hubitat. However the delay is very random. It will unlock sometimes after 1 second and sometimes after 30 seconds, and sometimes the logs will just say error. Is this because I don't yet have the repeaters?
If you put the hub close to one lock, put a repeater about half-way between the hub and the other lock. You may have to exclude/re-include the lock for it to route through the repeater.
i have the hub about 4 feet from my new lock right now. And it was working fine. Now it works like every 10th try. huge delay and sometimes it just gives error in log. Shouldn't at least the close lock work with no issues without a repeater?
Based on that though you really should have a repeater. 2 devices don't really make a mesh. As @aaiyar get a repeater in there, then re pair the lock to force it to go through the repeater.