Cannot Edit in Block Editor

Hi, all! TIA for your insight.

When I try to edit in the block editor, I get a white page that says:

The editor has encountered an unexpected error.

Next to this there are three buttons:

Attempt Recovery | Copy Post Test | Copy Error [see below for error text]

I updated to the latest version of WordPress (2-3 days ago?). Starting yesterday I couldn’t edit with the block editor, only classic.

I have tried:

-Deactivating and reactivating each plugin one by one.

-Migrating from Atomic Blocks to Genesis Blocks.

-Installing the Health Check & Troubleshooting plugin. My site health is good, per this plugin. With this plugin, you switch to a default theme (e.g., WP’s Twenty Twenty theme) and turn plugins on and off in troubleshooting mode. (Site visitors still see your desired theme and lose no functionality.) The block editor worked fine with all the plugins AND default theme – BUT – when I switched to MY desired theme in troubleshooting mode, the block editor broke again.

I’ve never had an issue like this with my desired (i.e., non-default) theme.

Here’s what I get when I hit the “Copy Error” button:

Error: Minified React error #130; visit https://reactjs.org/docs/error-decoder.html?invariant=130&args%5B%5D=undefined&args%5B%5D= for the full message or use the non-minified dev environment for full errors and additional helpful warnings.
at Rc (https://siemachtsewingblog.com/wp-includes/js/dist/vendor/react-dom.min.js:157:299)
at q (https://siemachtsewingblog.com/wp-includes/js/dist/vendor/react-dom.min.js:69:432)
at v (https://siemachtsewingblog.com/wp-includes/js/dist/vendor/react-dom.min.js:72:200)
at https://siemachtsewingblog.com/wp-includes/js/dist/vendor/react-dom.min.js:76:214
at T (https://siemachtsewingblog.com/wp-includes/js/dist/vendor/react-dom.min.js:87:146)
at ph (https://siemachtsewingblog.com/wp-includes/js/dist/vendor/react-dom.min.js:218:209)
at lh (https://siemachtsewingblog.com/wp-includes/js/dist/vendor/react-dom.min.js:126:409)
at O (https://siemachtsewingblog.com/wp-includes/js/dist/vendor/react-dom.min.js:121:71)
at ze (https://siemachtsewingblog.com/wp-includes/js/dist/vendor/react-dom.min.js:118:14)
at https://siemachtsewingblog.com/wp-includes/js/dist/vendor/react-dom.min.js:53:49

The page I need help with: [log in to see the link]