Well, if building an amp instead of buying, you will have issues because certain companies (*cough – Hypex – cough*) lock away their better tier 2000W N-core (https://www.hypex.nl/product/nc2k-oem/79) behind solely to companies for integration. So you cannot buy those on the open market and the Hypex 2000W older model UCD2K (https://www.diyclassd.com/img/upload/doc/ucd/ucd2k_oem/Documentation/UcD2kOEM_R9.pdf) has a THD+N that is all over the map, but that is the only one that can reach the over 1000W.
I’ve mainly looked at DIY amps. Now, if talking DSPs, make sure you pick one up that has at least an ADSP-21489 if you want advanced correction. Otherwise, you can do an OK job with an ADAU1701 for a crossover. What you pick will depend on your goals regarding DSPs, along with how much you care to learn sigmastudio. In the image attached, that is my WIP for a 3-way, although I think the FIR is going to be removed from it. That is for a Sure Electronics JAB5 (rebranded by Dayton Audio in their KABD-4100). I just doubt it will have enough taps left to do a proper FIR phase correction on the ADAU1701 after doing all that. But you still have a PEW, Crossover, time alignment (technically, you should be able to get away with only two on the schematic, but you should have the largest driver, usually a sub or the woofer, as the one without the time shift. Why? Because it is already the furthest away from the tweeter and plays the longest wavelengths. So you will be time shifting the mid and tweeter to match the time of the woofer. I went with a gain to be typed in instead of a slider. Why? Ease and accuracy. The signal detection is important to mute it when nothing is playing. The cascading slew volume controls helps to make it more exponential than linear, which is what people like when they turn up the volume know. Also a Gain and time delay before the infrasonic filter (high pass) is meant to time align both speakers with each other and to volume level for the target seating area. You can do even more with the ADSP-21489 SHARC.
But I haven’t flashed this to the unit yet, so I don’t know how many instructions I will have to cut. Just something I’m working on. Also going to do a similar as a 2 channel which I want to eventually buy this for a bookshelf speaker (https://www.aliexpress.com/item/1005001849585611.html?spm=a2g0o.productlist.0.0.542c144dsnIBIR&algo_pvid=5b4fffdc-072a-4a80-b6da-b31cc5761f04&algo_exp_id=5b4fffdc-072a-4a80-b6da-b31cc5761f04-47&pdp_ext_f=%7B%22sku_id%22%3A%2212000017847920780%22%7D&pdp_pi=-1%3B94.99%3B-1%3B21.37%40salePrice%3BUSD%3Bsearch-mainSearch ; review here https://www.audiosciencereview.com/forum/index.php?threads/3e-audio-sy-dap2002-review-dsp-amplifier.20114/ ).
But, that is woefully under-powered for your speakers you are considering, which would need, with an active crossover, just under 880W to drive it full tilt. Now, if you wanted to drive something to 400W, you might look at the Icepower 400A2 ( https://icepoweraudio.com/download/9283/ )would do alright (although usable is much less). You might look at the Icepower 1200A2 ( https://icepoweraudio.com/buy/as-series/1200as2/ ) as well, but still not where I’d like it to be (although some specs you just cannot get real good at higher watts without access to something like the N-core 2KW model or above, which is why the ones mentioned by @chedwin are so good but cost so much).
So I can point you at things to look at, but don’t know what would be best for you, nor do I know what you plan to do to address setting up the components if going the DIY route for amps, power supplies, and DSPs. Also, even if doing an active speaker, remember you can pull finished products out of their cases, make your own mounts, do connectors on the back panel, and wire it to the pulled board you mounted.
If you want high end 400W, then the Orchard Audio https://orchardaudio.com/ ; the Purifi (my choice if you have the money, although this cannot fully power the speaker, it is the budget balance with great performance, not to suggest Orchard doesn’t have great performance as well; https://purifi-audio.com/eigentakt/eval1/ ) ; and the n-core series available to the public (although I prefer orchard and purifi over n-core is spending that much).
So it depends, I suppose. But that is the DIY side. If you want a finished product, I can tell you Erin of Erin’s Audio Corner drives his home theater with Crown. And considering chedwin also mentioned them, you won’t be disappointed. But I don’t know amps outside of DIY that well, so would recommend listening to these guys, Toid, or ask over at DIY Audio Guy’s channel (although easiest way to get hold of him is patreon, so you can choose if you want to do that).
Also, good dyno testing of amps at Williston’s channel on Youtube might be worth checking out. https://www.youtube.com/c/bigdwiz
That won’t show you how the response looks per power in a chart, but you can see where it hits clipping under certain conditions with a high end benchmarking unit. Worth a look.
Hope that helps.