Qualifications
Employers looking for a Solution Architect will be more interested in your experience than formal qualifications. This is certainly true within the UK. There are no formal educational prerequisites. As is the case with most jobs, the specifics of whatever degree you did years ago or higher education achievements are largely an irrelevance.
A lot of general guides from employment agencies or careers websites outline a need for University/college degree. This simply isn’t true. The role of Solution Architect demands years of exposure to the many facets of working within a technology discipline within a large complex organisation. No single, or even multiple, degrees will provide that experience.
The most relevant formal qualification which would be of use to new junior Solution Architects would be a degree in Software Engineering. That demonstrates a basic understanding of how software solutions are created.
In summary, the ideal qualification is job experience gained in a technology related area of a large organisation. That could be a few years as a senior developer, devops, network/infrastructure, security or technical analyst areas.