Opinions are varied on this. USA Archery feels that the bow arm should be locked. Of course, they primarily deal with shooting recurves. Rick Welch teaches his students to keep an unlocked and slightly bent bow arm for all types of bows. I've only had one bow, a hybrid longbow, that gave me elbow pain in my bow arm, and I ended up selling the bow. I don't know why it gave me elbow pain, and it was probably just a coincidence that it happened with that bow, but life is too short. I shoot all of my bows now with a locked bow arm, and have had no recurrences of bow arm elbow pain since then.
Elbow pain is usually usually caused by tennis elbow. There are two mistakes you don't want to make if you have tennis elbow. First, to go on doing what you're doing without treating it will just make it worse until it gets really bad. Second, to stop doing what you're doing and give the elbow complete rest will stop the pain temporarily, but it will return as soon as you resume whatever activity causes the pain. This is because you're not treating the issue that caused the pain, which is microtears in the connective tissue and muscles of the elbow, so the muscles are getting weaker from lack of use making recurrence more likely.
The Internet is full of suggestions for treating tennis elbow, like doing reverse wrist curls with cans of peas, which you can try. I used torsion bars, like these from Amazon:
https://www.amazon.com/Serenilite-Flexible-Resistance-Exerciser-Tendonitis/dp/B08S7LFTN8/ref=sr_1_6?crid=1NU0H7V1NVCYD&dib=eyJ2IjoiMSJ9.D7_PQ_R_wHrJ6rgt6YoqUojW7oxb9sTl3iEGaSUQoz3uwRVUMtAbbzLgfzoZz4omxisAFLu1YAKTsmt4uz1p6wRpc3HZzhcusGqCqD1Xf12qJU7QtVo8eaEB1CVX2FAu.cY9uOQKn-IEbvib1T4p1Gg6Y4OnyIXil8S2aCoFH268&dib_tag=se&keywords=Torsion%2Bbar%2Bfor%2Btennis%2Belbow&qid=1709303817&sprefix=torsion%2Bbar%2Bfor%2Btennis%2Belbow%2Caps%2C181&sr=8-6&th=1 which seemed to help, and you can find vídeos on YouTube about how to use them.
In any event, if you decide to bend your bow arm and it helps, you are in good company. Just don't tell USA Archery that you're doing it. Even if tennis elbow gets really bad, it's not generally very serious and can be reversed with proper attention.