And when disabling plugins, be sure you clear the WHOLE cache etc of Fastest Cache. FC doesn't do that automatically.
I use Cleantalk antispam,
Bad, bad, that one is a resource hog and not great. I would suggest you to use WordFence instead, along with perhaps WPBruiser. They work great along each other and have all the protection you might need. Try them out when you can.
@percysgrowroom if you pay more than $44 to $67 for hosting, I can suggest you a good host where you could even get a dedicated server with all the resources allocated to you alone for that price.
If you pay a lot less, well, like it has been suggested, look for a host who specializes in WordPress hosting and has fully managed support for migrations and after migration maintenance. The host I use also has WordPress specialized hosting, but I haven't tried that. I have gone with dedicated servers for all my needs for a few years now, these days you can get great offers on dedicated servers for great prices.
I see that DB issues are not appearing anymore.
So you should take steps to solve also the out of memory errors (see your today's log).
Can you DISABLE that Chat plugin for a while?