Can you show us HERE on this forum an example ?
Also this is the most optimized forum, talking about SEO and everything. Well respected.
An example: This url
href="https://www.warriorforum.com/search-engine-optimization/1348105-how-long-do-you-wait-after-seo-optimizing-content.html?amp=true"
has as title in meta:
<title> How long do you wait after SEO optimizing content? | Warrior Forum - The #1 Digital Marketing Forum & Marketplace </title>
As you see the lenght is also very very long.
So i think you should not worry about the SEO myth and go on with your forum. Your forum will rank if it is good and has some good VOTES (backlinks).
I worry about it because it will be a problem if every title is 2/3 the same. Can anybody help to fix this problem?

