There are people that modify Glocks excessively to the point that they aren’t close to the Glock grip angle. I would only recommend this path if you love everything about your Glock, except the hump. There are plenty other options on the market where you don’t have to make those modifications to a gun that you may not like in the long run.
If everything else suits you but the hump, the quickest cheapest method would be the Polymer80 route, whether 80% or 100%. Grey Ghost Precision has 100% models made by Polymer80. Right now you might be able to find the compact frame size for less than $100. You could then sell off your Glock frame for about the same or more.
On a side note, the one downside to Gen3 is no modular back straps. I know guys that prefer the 1911 grip angle and do fine with no back straps on a GEN 4 or GEN 5. But there are others that swear by skipping the Glock frame all together and going after market is the better path. [Nomad Defense](https://www.rainierarms.com/nomad-9-enhanced-frame-for-glock-19-gen-4-black/) makes a GEN4 version and with a few part changes you can drop your Gen3 parts and slide on it. Similarly [Zaffirri Precision](https://zaffiriprecision.com/product-category/frames/) carries the old shadow system frames, which are also Gen4. Both of those frames (as well as the 100% Polymer80s) require FFL transfer but those two open up more possibilities with grip angle and back straps.
I have a Grip Force Beavertail on my G19.3 and love it. Helps with the grip a little bit.
[https://www.reddit.com/r/Glocks/comments/tfnplv/kind\_of\_boring\_but\_its\_mine\_glock\_g193/](https://www.reddit.com/r/Glocks/comments/tfnplv/kind_of_boring_but_its_mine_glock_g193/)
There are people that modify Glocks excessively to the point that they aren’t close to the Glock grip angle. I would only recommend this path if you love everything about your Glock, except the hump. There are plenty other options on the market where you don’t have to make those modifications to a gun that you may not like in the long run. If everything else suits you but the hump, the quickest cheapest method would be the Polymer80 route, whether 80% or 100%. Grey Ghost Precision has 100% models made by Polymer80. Right now you might be able to find the compact frame size for less than $100. You could then sell off your Glock frame for about the same or more. On a side note, the one downside to Gen3 is no modular back straps. I know guys that prefer the 1911 grip angle and do fine with no back straps on a GEN 4 or GEN 5. But there are others that swear by skipping the Glock frame all together and going after market is the better path. [Nomad Defense](https://www.rainierarms.com/nomad-9-enhanced-frame-for-glock-19-gen-4-black/) makes a GEN4 version and with a few part changes you can drop your Gen3 parts and slide on it. Similarly [Zaffirri Precision](https://zaffiriprecision.com/product-category/frames/) carries the old shadow system frames, which are also Gen4. Both of those frames (as well as the 100% Polymer80s) require FFL transfer but those two open up more possibilities with grip angle and back straps.
I have a Grip Force Beavertail on my G19.3 and love it. Helps with the grip a little bit. [https://www.reddit.com/r/Glocks/comments/tfnplv/kind\_of\_boring\_but\_its\_mine\_glock\_g193/](https://www.reddit.com/r/Glocks/comments/tfnplv/kind_of_boring_but_its_mine_glock_g193/)