Hello,
Thank you for contacting the support and sorry for any inconvenience that might have been caused due to that.
Assuming you are using the latest version of all the plugins and the themes (please update if not yet), it would seem like a conflict with one of the plugins or the theme you are using.
To determine that, please follow this troubleshooting guide:
https://rankmath.com/kb/check-plugin-conflicts/
Only the site admin would know and your users won’t be affected by this troubleshooting.
If the issue persists, please record a video screencast using a tool like Loom showing the troubleshooting and edit the first post on this ticket and include your WordPress & FTP logins in the designated Sensitive Data section.

It is completely secure and only our support staff has access to that section. If you want, you can use the below plugin to generate a temporary login URL to your website and share that with us instead:
https://wordpress.org/plugins/temporary-login-without-password/
You can use the above plugin in conjunction with the WP Security Audit Log to monitor what changes our staff might make on your website (if any):
https://wordpress.org/plugins/wp-security-audit-log/
Please do take a complete backup of your website before sharing the information with us.
We really look forward to helping you.
OK, so no answer. Only way how can I change URL of categories is disable Rank Math and then enable it again. I will try Yoast SEO again. If it dont will crash site as Rank Math, I will stay with them…
Hello,
Thank you for the update, and apologies for any inconvenience this issue may have caused you.
It seems that you have marked this ticket as already resolved.
We respect your decision to switch to Yoast.
However, please feel free to contact us anytime if you want us to further investigate this issue on your site using Rank Math.
Looking forward to helping you.
Thank you.