I have disabled almost all other plugins, but the Toolset plugin still gives me rows insted af columns.
It seems you didn't disable the Gutenberg plugin, that's what breaks the grid block, too.
I've reported that as well, and it will get fixed soon. (If it is affected by the imminent WP 5.4 release it will be fixed in a hotfix for Views and Blocks, otherwise it will be included in the next planned release, which is in any case due fairly soon.)
I've seen an internal ticket about the style settings with WP 5.4, so that will also be fixed soon.