I asked the same question about 14 months ago: Best Practise for Roon - Networking
At that time my network was far from ideal since I used Powerline adapators to distribute ethernet around the house:
Nevertheless, I still had a good Roon experience.
Since then, my home network has been improved a lot (I elliminated the powerline adaptors and established a 10Gbps backplane) and now looks like:
I have never had any problems with Roon.
I do not use a MESH WiFi system - the Asus routers that I use can propagate WiFi to a reasonable standard throughout the house (which is not large) but, with this latest network implementation, I don’t normally use WiFi for audio (or video) streaming. It is occaisionally used to casually stream to phones and tablets. WiFi connected phones and tablets are used as control surfaces.
I have a configured my network simply: I have all my computers, phones, tablets and streaming devices on a single logical network (not separated by use of VLANs) and I use unmanaged switches throughout for simplicity.
I use a NUC11 for my Roon Server (on the ROCK compatible hardware list) but I don’t use ROCK (I used to but migrated to DietPi nearly a year ago).
All dedicated audio zone/endpoint devices are connected by ethernet and network capacity is planned such that non-audio activities (like editing video on my NAS) does not saturate any of the inter-switch links to the extent that Roon (or any other activity) is starved of network bandwidth.
My broadband is reasonably good - 500Mbps down/ 73Mbps up - but importantly, it is low latency FTTP GPON based service. Previously, I used a 1Gbps down/50Mbps up DOCSIS service which had much higher latencies. Many internet related activities are actually faster on the new service despite the reduced download data rate.
Finally, whilst I have a number of hi-res albums, I don’t have (and I don’t believe in the need for) any local library albums sampled at higher than 192kHz.
Of my four main endpoints, one is an ARCAM ST60 streamer which has been absolutely flawless since I bought it (although I believe that there were some teething issues with this device) feeding into a 25year old Denon 3802 AVR with a 3.1 speaker setup (I used to have a 5.1 setup but room use and aesthetics demanded the removal of the surround speakers 
)
The remaining are RPi4’s running DietPi and Roon Bridge - one using USB to a FiiO K9 PRO headphone amp, one with an IQAudIO DigiAmp+ HAT (30W/channel max) and thence directly into passive speakers and one with an IQAudIO DacPro HAT into a Ruark R1 mk 4 radio/alarm clock.