Not a big fan of installing EOL browsers or plugins, especially from third-party sites when there are much better options available.
Adobe still offers their developer tool Adobe Flash Projector, which will allow you to view Flash content without using a browser.
You can download the Projector here:
Adobe Flash Player - Debug Downloads
It's a standalone application, just open it, and then Choose open and enter the path of the file or site you're trying to view.
There's also the open source app Ruffle, which is a separate implementation of Flash:
Ruffle | Flash Player emulator written in the Rust programming language
Or even a rougher emulator like Lightspark:
Lightspark
For just plain swf files, you can play those in something like VLC (there's not much it won't play).
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