It's not black and white, but cloning a product is just not nice. The legality is probably fine, there might be an argument for copyright infringements, but unlikely to get any result.

Imo it's also good to realize in this kind of software, patterns and UI are very core to the product, so you are copying the essence of what this company has spend tons of time and resources to develop. Fintech might be different as it's less about UI.

Then there is also a difference between UI patterns and branding. The first: It's good to follow standards and expectations, the second should just not be copied imo.

Another factor is asking money for it, which it looks like they intent to do. I think that makes it even weirder to clone an existing product as now you try to compete and profit from other peoples work.

There is a fine but clear line between inspiration and copying, and imo this crosses the line.

Even if legal I would not use this product for that reason, and imo it reflects poorly on the people doing it.