My understanding is that you can do this, but it requires some additional setup.
Each Switch has multiple Z-Wave association groups, each with a specific set of commands.
If you properly configure groups 2, 3, and 4 on Inovelli’s switches, my understanding is that you can have (for example) a 3-way dimmer setup where all 3 switches control a single load on/off/dimming and behave as a single circuit even while holding down the dimmer, all without a hub.
Group 2 only sends basic set commands (i.e., “On”, “Off”)
Group 3 only sends “multilevel set” commands (i.e., “set output to 70%”)
Group 4 only sends “multilevel set” dimming commands (i.e., “start dimming down”, “stop dimming”, “start dimming up”)
Using group 4 associations, you can have a single switch tell the other switches when it starts dimming (causing all switches to start dimming), when it stops dimming, and with a group 3 association, the final value after its done dimming (keeping the LED bars in sync). The Dim rate isn’t communicated, so you’d want to make sure the switches are all configured with the same dim rate— otherwise the LED bars might get out of sync while dimming, before snapping to the correct level when the switches stop dimming.
There are several threads and guides floating around on the forums here with specific details on how to create this configuration with the various common hubs, but you should be able to do what you want, i.e. walk up to a 2-way switch setup, press and hold the up button to dim the light up, and watch the paired switch across the room dim up in sync with the switch you’re touching, all without having to go through your hub, with the only limitation being the number of switches you’re keeping in sync as a single “circuit”.
I think that’s part of the trade off between a vendor-locked vertical integration and a compatibility standard. In theory, I can use any properly-designed Z-wave device from any manufacturer with a hub or other device from any other manufacturer. I can use Inovelli Switches with Inovelli Lights and a Hubitat hub and Schlage door locks and GoControl garage opener and Aeotec water leak detectors.
Each brand can specialize in what they know and do best, and/or be replaced if they aren’t continuing to fulfill their niche effectively without having to throw out the entire system. The trade off is configuration isn’t going to be as nice or new features universally integrated or perhaps push the boundaries as much.
That, and honestly, when it comes to light switches, Inovelli is king of features and service. Especially once you consider “Supports Z-Wave” to be the major feature that it is.