There are some protections, but yes, they are much more limited (in particular, anything that would generally be classified as automatic unfair dismissal is still protected, for instance for whistleblowing, joining a trade union, firing someone for raising a health and safety concern or for going on maternity leave).
You will likely still want to capture and document the genuine reason under either performance, absence or conduct grounds in order to protect against any invalid claim that the dismissal was because of a protected reason if it was brought to tribunal (when in reality it wasn't).
Although it may still be better to go through formal redundancy so you can make the redundancy on the basis of performance rather than just length of service.
You mentioned that "they are entitled to learn why and what has been done to try to keep them", but actually it's much further than that - they are entitled to be part of the conversation and to propose alternatives to the dismissal which the company is legally obligated to consider.
As an example, if the redundancy proposes to make a team redundant and split that teams responsibilities across other teams, the consultation might raise that the team being made redundant could take on additional responsibilities and down-size as an alternative which could result in fewer redundancies. Similarly, employees could suggest an initial round of voluntary redundancies first to reduce the people impact (particularly if there are employees nearing retirement age). The employer is legally obligated to genuinely consider these alternatives, however if the action was taken immediately to disband the team and place employees on gardening leave it is much more difficult for them to argue that the consultation was 'genuine'.
If a genuine consultation is not held, where alternatives are listened to and genuinely considered, this could then be brought to an employment tribunal and could open them to unfair dismissal claims.
Garden leave is not a necessity (particularly if you have structured your company so a single employee cannot go too rogue regardless - if a single bad-apple employee can take down coinbase then they have bigger systemic risks!).
See here: https://www.gov.uk/redundancy-your-rights/consultation
Revoking access and not allowing users to complete their jobs would often be seen as a failure to consult (see, for instance, the recent P&O ferries dismissals where they immediately removed ship access from the crew, replaced them with oversees workers, and then began consultation. This was a failure to consult and was found to be illegal).
People tend not to do rash things anyway during this period, as gross misconduct during that time would mean the employee is instantly fired regardless with zero redundancy pay. Treat people fairly and as adults and they tend to behave fairly and respond as adults. Treat people as untrustworthy and rash, and they tend to respond with the same.