Website maintenance nightmare!

Okay, I'm at my wit's end here and urgently need some advice. We run a small but rapidly growing SaaS, and while our product is gaining traction, I'm completely drowning in server and infrastructure issues. It's diverting almost all my focus away from actual product development and strategic growth, which is exactly what we need right now.

• Current Setup: We're self-hosted on a custom server setup that I initially configured to save costs.
• Growth Pains: The problem is, our traffic is spiking, and with that come performance issues, unexpected crashes, and just general instability. It feels like I'm constantly firefighting.
• Lost Focus: I'm spending excessive time on server issues – debugging, patching, monitoring – instead of building features, talking to customers, or planning our next moves. This isn't sustainable.

I've tried so many things, but nothing seems to stick, and the problems just keep piling up. It's a never-ending cycle of fixes that only provide temporary relief.

• Downtime: We're experiencing frequent outages, sometimes multiple times a week, and I know we're losing users and potential customers every time the site goes down. It's incredibly frustrating.
• Slow Performance: Even when we're up, page loads are often unacceptable despite implementing caching layers and a CDN. Users expect instant, snappy experiences, and we're just not delivering.
• Security: The constant threat of attacks and the need for manual patching is a huge burden. I'm always worried about a breach, and I simply don't have the time or specialized expertise to keep everything watertight.
• Attempts: I've tried optimizing the database, tweaking web server configurations, and setting up basic monitoring, but these are all just band-aid solutions. They might work for a few hours or a day, but then a new problem crops up or the old one resurfaces.

I'm at the point where I desperately need to offload these tasks. My main goal is to reclaim my time for the business, ensure 24/7 reliability for our users, and significantly enhance our security posture without me having to become a full-time system administrator. I'm convinced we need a truly reliable managed service provider, specifically for comprehensive website maintenance.

So, my main question is: How do I find a truly reliable website maintenance and managed service provider that can handle a growing SaaS? What are the crucial criteria I should be looking for beyond the usual marketing speak?

I also have a few specific concerns:

• How do I avoid vendor lock-in?
• What's a realistic budget for a growing SaaS when it comes to these services?
• How do I verify that their "24/7 support" and "proactive monitoring" are actual services and not just buzzwords?

I'd really appreciate any insights, especially from those who've made the leap from self-hosting to managed services. What specific services should I prioritize from the get-go? Do you have any provider recommendations (good or bad experiences)? Any red flags to watch out for?

Thanks in advance!