Internal Server Error: SQLSTATE[42000] 1118 Row size too large
You're running into a MySQL/InnoDB server limitation that commonly occurs with a significant number of columns in a single table.

Fortunately, there are several documented workarounds for it:

https://stackoverflow.com/questions/15585602/change-limit-for-mysql-row-size-too-large

https://www.percona.com/blog/2011/04/07/innodb-row-size-limitation/

https://dba.stackexchange.com/questions/6598/innodb-create-table-error-row-size-too-large

From the Craft side, another workaround would be to re-think your information architecture. Currently, most fields in Craft have their content stored in the craft_content table in the database, so when you have a lot of textual fields on the site, you'll see the error you're getting.  The exception to this rule is Matrix fields, which get their own table where their content is stored.

If you can move any of those fields into Matrix fields where they make sense, you'll take them out of the craft_content table helping mitigate the issue.