I can tell you why it didn't work on our site. I was running a pre-3.4.2 dev release on our site which didn't have the fix for the SEF router. I installed 3.4.2 now and the link works.
Please make sure that your My Tickets link is not a submenu of the ATS main menu (ticket categories). If your site is already structured differently you can create a menu item in a hidden menu and replace the old My Tickets link with a System, Alias menu item.
This change is necessary because of the way Joomla 4 component SEF routers work. In fact, this is how Joomla 3.4 and later component SEF routers work, it's just that Joomla 3 still has backwards compatibility with the old SEF routers which use the Joomla 1.6 to 3.3 methodology.
So far we had not updated our SEF router to keep backwards compatibility. However, we reached a point where ATS would be unusable in Joomla 4 if we didn't upgrade our SEF router. The downside of upgrading the router is that some black magic I had done with the one-off views, such as My Tickets and Buckets, would no longer work. I had to modify that code a bit and it was, indeed, very broken in 3.4.0 and 3.4.1. In 3.4.2 I fixed it but you may need to move menu items around to prevent Joomla reporting the wrong (least specific) menu item as more relevant to the router.
Having worked with Joomla's SEF routers I understand why literally nobody else is implementing a routing system with so many degrees of freedom. Everyone else registers what would be a per-component and per-view prefix, regardless of the menu structure visible to the user. In Joomla we're trying to do that PLUS keep coherence between the menu structure and the URL structure. Each method is diametrically opposite to the other and, yet, we're trying to make them work together. Hilarity ensues, for "oh my God I spent five days on this, why is it still doing funky things" values of "hilarious".
Nicholas K. Dionysopoulos
Lead Developer and Director
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