@woolysaurus- A Roku remote without a functioning OK button is pretty useless.
I've rejuvinated remotes with non-responding buttons for various devices over the years by taking them apart and renewing the contact areas on the button membrane with a conductive paint (automotive rear window defrost repair kit). This solution isn't for everybody as disassembling and reassembling these things can be fairly daunting.
I believe both Premiere+ releases came with a point-anywhere WiFi-direct "Voice remote". You can order either the Voice Remote or Voice Remote Pro from Roku via this Roku Accessories Page (but not the Enhanced Voice Remote which only works with certain models other than the Premiere+). You can also find them at many retailers such as Amazon, Wal-mart, Target, etc.
If your Premiere+ is out where a direct line-of-sight infrared (IR) remote can reach it you can also use the Roku Simple remote found on that same Roku page and elsewhere, or any inexpensive universal IR remote you find locally or online that says it supports Roku devices, as all Roku IR-capable models use the same set of IR commands.
In the meanwhile, if you have a mobile phone with WiFi connection capability you can install the Roku app which includes remote control capabilities. (For remote capability, you want the Roku app, not the Roku Channel app.)
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