They have these isolation videos posted where members of a band are playing a song together, each in a different window. It looks good but the truth is it isn’t taking place in real time. Each person is sent a reference track, they record a video playing their part along with it, then email it back to someone who pieces it all together. They can’t all play from remote locations in real time is because of latency, a time delay. Maybe with super fast computers, the ultimate optical internet speed end-to-end, and lossless data compression, but that isn’t the real world.
Yes, you can plug into your amp, feed in an mp3, monitor with headphones, feed that into an interface box, into the computer and record.
I would load the MP3 into a track on the DAW, plug the bass and headphones into the interface, and record a new track. This allows you to apply any plugins such as a limiter or EQ either while recording or post recording. You want a limiter to avoid any horrid distortion. No amp needed, it could be a source of hum and hiss type noise. Saving a copy to link to on a web page is doable. Just like we do on talkbass in posts.
If you are feeding live out to a phone in real time, there will be a latency. If anyone at the other end says anything there will be more of a delay in getting back to you. Syncing could be a problem if the latency delays are too long.
They all say, “High-Definition Recording Made Easy” on the box. No easy about it! All this stuff comes with steep learning curve before you even play a note.