It's simple really.!! . . . If you need a machine for business and have the work for it then buy one or have one made by someone like me as you are up and cutting quicker, so earning quicker. I've built machines for people costing £5k and the machine as paid for its self within the first few months or even weeks in some cases.

However, if your DIY and it's just for pleasure and have the time, patience along with the tools then just get on with it start building forget how long it takes, it doesn't matter. What matters is how you do it.
If you try to cut corners and do it on the cheap then at best you'll have an under-performing machine and at worst you'll have a pile of expensive scrap. Cheap solutions like using Mdf, linear draw slides, chains and even belts if not done correctly are a waste of time if you want a serious machine.
The only way to have a machine that's worth the effort is to do it correctly from the start and buy components that are fit for purpose. This doesn't need to be expensive either, many secondhand industrial components can be found that even if 10+ yrs old will still be far far superior to any of the cheap alternatives used.

However, you don't even need to do this if you are prepared to buy from china and look around. With £2k if you shop around and buy wisely you can build a very decent machine that will match and in some cases greatly outperform many of the machines you mentioned. You just have to wait and get your hands dirty, which is half the fun if your into DIY.

Forget any Cheap hack routes they don't work well or last longterm.

It really is that simple. If for DIY Build it good with decent bits. If a business just Dig deep buy it and earn it back quicker.