Officially I can't say, but there are a few eBay sellers (and likely sellers from other sites) that sell full Steam Deck screw sets for low prices. Here's just one example I've found. Don't anticipate third-party sellers to package a specific type of screw as opposed to either complete device replacements or things like back cover screw sets. I can't speak to quality, but the seller notes for similar sets note a deviation of 1-2 cm for the error margin. At 5.23 mm, your measurements seem comparable. You can take a dig on other sites like Amazon and Aliexpress for more options with these things in mind. Alternatively, you might be able to custom order based on your measurements. The listings I've seen for full replacement sets on eBay have included images with screw measurements that you might be able to cross reference, though I don't know if you'd trust them outside of being a corroborative reference to your own numbers.
I hope this has helped at least a little and that you manage to find the screws that you need.
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