Website Builder Software Resources

I'm researching which website builders actually hold up for small agencies juggling multiple client sites at once, since the bigger pain point at that scale is usually management overhead rather than any single site's features. Inside Website Builder, Wix, Squarespace, and Bitrix24 come up most for agencies managing several client accounts.

1. Wix: offers an agency-oriented workspace for managing multiple client sites from one dashboard, which cuts down the need to log into each site separately.
2. Squarespace: strong template consistency makes it easier for a small agency to deliver a polished result quickly across several client projects without starting from scratch each time.
3. Bitrix24: useful for agencies that also want CRM and project tools tied to each client relationship, not just the website itself.
4. Appy Pie: a lower-cost option some smaller agencies use for simpler client sites where budget is the main constraint.
5. Vendasta AI Platform: built specifically for agencies reselling digital services to local business clients, with website building as one piece of a broader white-label toolkit.

For agencies running several client sites on one of these, what actually caused the most friction as your client list grew, billing and account management, or just the sheer time it took to update each site individually?

I'm researching website builders specifically through the lens of avoiding vendor lock-in, since a lot of builders make it easy to create a site and much harder to leave with your content intact. Within Website Builder, WordPress-adjacent options aside, Wix, Squarespace, and Bitrix24 are worth comparing on this specific point.

1. Wix: offers some export options for content, though its page structure is proprietary enough that a full migration to another platform usually means rebuilding design elements rather than a clean transfer.
2. Squarespace: similar story, content can be exported but design and layout don't transfer cleanly to another builder, so switching later still takes real rebuild time.
3. Bitrix24: as a broader business platform with a website builder included, data portability tends to be better since it's built around CRM and business data rather than a closed site design system.
4. Instapage: landing page focused, with simpler page structures that are generally easier to recreate elsewhere than a full proprietary site builder.
5. Leadpages: similar landing page simplicity, which cuts down migration pain compared to full site builders with heavier proprietary structures.

For anyone who's actually tried migrating off one of these builders, how much of the site did you realistically keep, and how much ended up being a rebuild from scratch on the new platform?

Have anyone tried canva for wireframing ? How good it is with Canva AI ?