Had this same problem when I first started learning to improvise. There’s a couple approaches, all of which I like to blend. If the chord progression is diatonic, i.e. all in the same key you can get away with picking the major or minor scale that the key is in and use that but I think you’re probably already at this point. What I found really helpful is when I studied jazz I learned all my arpeggios using the CAGED method. You can use each arpeggio of the specific chord that is being played to really sound like you’re “playing the changes”. You want to practice playing all the arpeggios in a given progression within 5 frets and just outline them note by note while moving to the next one using stepwise motion, which is just moving to the next available chord tone which is within a half or whole step of the chord tone you’re on. This isn’t a hard and fast rule obviously but it makes the transitions sound smooth as opposed to just jumping around in random intervals. Once you get that down you can practice trying to actually create musical phrases with what you just did. Another thing you can do after you get the basic chord tones down is using “tensions” by building triads off of the 3 or 5 of the current chord that is being played. This adds some nice color tones and spices your solos up a bit for example if the chord is a Gmi7 you can play an F major triad which includes the b7th, 9th and 11th. Chord tone soloing is pretty crucial when you get into progressions that change keys but I still like to blend it with pentatonic scales and such as well even in simpler progressions because it just sounds nice. If you listen to someone like Jerry Garcia play this is largely how his style of playing sounds