I don't have a Streambar, but I've had experience with 6 different Rokus over the last few years. I can only share my experience with the two routers I've had in that time.
I had an old Western Digital router (WD is no longer in the router business) that only had the 2.4 GHz wifi band when I got my first Roku 2XD. I would lose my wifi connection several times a month, requiring me to restart the router, restart the Roku, and re-establish the wifi connection. This even though none of the other wifi devices in my house had any problems. I just figured the Rokus were less able to recover from router network instability than other devices, or maybe it was that the Roku continuously operated for hours at a time making it more likely to be in operation if the router hiccupped than a phone or tablet that only actively networked in short spurts. It continued on this way for several years, as I added Rokus to additional TVs and eventually updated them, although most of the time the problem occurred with whatever Roku was in the livingroom installation, which is the most used by far.
Then in July 2021 I replaced the old WD router with a new ASUS RT-AX3000 primarily in order to add the 5 GHz wifi band and get its higher rated throughput. This router has been rock solid in that time. In the year and a half since putting in the ASUS my Rokus have never lost the wifi connection or forced me to reconnect.
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Streaming Stick 4K+ 3821 | Streaming Stick+ 3810 | TCL Roku TV 43S245/C107X