I am not sure that is correct. In such setup (aka repeater) the WLAN bandwidth suffers a severe bandwidth penalty. Having said that I do not know however whether there is a similar penalty on the bandwidth in a MESH scenario.
That is what EasyMesh aims for
removes the need to stay within a single-vendor ecosystem
Too bad that there has been no response from the developers.
To my humble understanding EasyMesh™ utilizes IEEE 1905 and unless I am mistaken such has not been implemented as of yet in either OpenWRT or TO.
Adoption rate of EasyMesh™ amongst router/ap vendors appears slow, most likely for commercial reasons (their bottom line) but perhaps also performance claims, whether true or not.
Not necessarily unless the other device utilizes IEEE 802.11s https://forum.turris.cz/t/question-about-the-turris-omnia-does-it-support-802-11s or in case Turris products would be EasyMesh™ certified.
Whilst EasyMesh™ utilizing IEEE 1905 as an abstraction layer (OSI model layer 2.5) to exchange Control Message Data Unit (CMDU) with 1905 neighbours those CMDUs are communicated directly over Layer 2, which could be IEEE 802.11s or proprietary vendor solutions.