Reddit mentions of How to Play Bebop, Vol 1

This concept of playing modally over a diatonic progression is kinda long-winded and pointless, imo. and not really how it's done.

Besides that, telling him to "play" the relevant mode for every chord doesn't help him any more than telling him to just play the major scale over it all.

I mean, we're trying to play music, not run scales from the root, how do you change mode from dorian to mixolydian in the middle of a line before you realize you're just playing ionian anyway?

It's the same note set, unless you know how to place them rhythmically to match the harmony, you're not doing anything different by just mentally shifting gear from dorian to mixolydian to ionian.
And, if you do know how to form lines to place the chord tones on the downbeats, you have no need to switch from mode to mode every bar because you'll know it's all part of one whole.

e.g., if I play this line, I'm not changing from dorian over the ii, mixo. over the V and Ionian over the I, yet you still hear the changes because it hits the chord tones on the downbeats.

It's all C major with a single added chromatic passing tone to make the chord tones line up with the downbeat.

For a further example, that line is over one chord per bar Am7-D7-Gmaj7 but the line would also work if it was two chords per bar Am7-D7-Am7-D7-Gmaj7. Would you say it changed mode 4 times?

Improvisation is hard enough without having to think about changing modes for every chord in a diatonic progression.

Learn your arpeggios, learn where the chord tones are and learn how to make scalar lines that hit the chord tones on the downbeats of the bars. Learn to add some tension, especially over the V and you'll sound like you're playing the changes.

Work on making lines that combine arpeggios and scales, how to use a scale in a musical context instead of running it up and down and, most importantly, work on hearing lines in your head before you play them, eventually you'll get to the point where your brain is screaming at you to play a certain note or phrase, that's what improvisation is about.

Here's some bebop scales you can check out, they're 8 note scales (basically 7 note scales with an added chromatic) that flow better over changes than 7 note scales, since they place the chord tones on the downbeats.

Also, look into David Baker's How To Play Bebop books for practical applications of scales in jazz, the Bebop Bible and Bert Ligon's books are good too.

This book has some good exercises: How to Play Bebop, Vol 1 https://www.amazon.com/dp/0739020404/ref=cm_sw_r_cp_api_i_hTIPCb5KP3C7Y

ETA: obviously this is not specific to guitar but I think the Bebop fundamentals are portable across instruments

David Baker's "How to Play Bebop" is a good starting point.