need help getting mod_rewrite to resolve blog url properly

My full WP URL is https://www.richardsilverstein.com/tikun_olam/.

Carthik has written some mod_rewrite rules that are redirecting the following urls to my site:

richardsilverstein.com
https://www.richardsilverstein.com
https://www.richardsilverstein.com

But there is one URL which will not resolve properly with the rewrite rule Carthik is using:
https://www.richardsilverstein.com/tikun_olam (which omits the final slash). I get a “requested url does not exist” error when I attempt to use it to get to my blog.

Here’s the existing mod_rewrite rule:

RedirectMatch permanent ^/$ https://www.richardsilverstein.com/tikun_olam/

Is there some way I can get the non-resolving url to work too w/o messing up another part of Carthik’s mod_rewrite structure?

And then once you help me fix that, I’ve got a hairy mod_rewrite problem with images fr. my old blog not displaying properly in my new one (possibly because old images are in one folder & new ones in another). See this post: https://www.ads-software.com/support/topic/37201 .

After fixing those 2 issues blog life would be a dream.