If you think Construct 2 can't handle graphically intensive games, then as ever, rendering is bottlenecked on the GPU. So if you switch tool because of that, the hardware isn't going to be any faster, and the performance won't be any better.
I think some people switching tools have hardware-bottlenecked games and are eventually going to realise it was never C2's fault. I do see a lot of games bottlenecked on the GPU, and everyone knee-jerk blames C2, HTML5, Chrome, or anyone or anything else. I don't know why it's so hard for people to believe they've fully utilised the hardware? The engine is designed to let you do just that. I'm happy to be proven wrong, please send me your projects and all that, but it usually only confirms the point. I imagine some people will wander from tool to tool always thinking everyone's engine is awfully slow, never recognising that hardware is a limited resource.
Just to pre-empt how this discussion usually goes: now someone's going to shift the goalposts and talk about some random bug or some quirk that we fixed, or some other problem they had at some point, or start listing their personal laundry list of things they want changed. That has nothing to do with GPU performance. On this specific point, C2 is as good as a native engine, and I stand by that.
I wish I could spend the time to help find the source of slowdown, lag and jank in C2/C3 and all its Third Party wrappers, I really do, because I love what you and Tom have made on the editor side of things, both in layout and events.
However, I don't have that time. I can only tell you that I experienced much better performance and compatibility in Unity when remaking the same game we had prototyped in C2 (actually, with better special FX and a higher output resolution thanks to upscaling a deferred renderer/render texture), and that I also find both Unity and Construct Classic make "smoother" running games that don't feel janky (even if the native runs at maybe 30fps, it doesn't jerk like C2 can at 59fps).
I'd really like to recommend again that you use your own tool to make (and release/troubleshoot) a full sized platformer game (on at least Steam for Windows) and experience the issues that others like myself have reported here. I'd even subscribe/pay for a C3 subscription just to see some work on that happening/it release over the next 2-3 years.
And if you prove me wrong? Great! Share your knowledge with us on how to best make large games!
If I prove you wrong? That's still good, because now you know best how to debug and optimize C2/C3.