I would recommend adopting Agile at a comfortable pace, which usually isn't all at once. Start with the core principles of Agile that your team is interested in the most and learn to apply them really well. Once your team is comfortable with what they have tackled, then continue to gradually introduce more Agile practices. This keeps things at a nice even pace and rather than it feeling like a process change that can be cumbersome it feels like adopting a new tool.

I would recommend at least setting a timeline out for your team though. Start by saying "We want to get really familiar with using a taskboard, and in 2 months we'll consider adding something new".

I like to use ideas from Throughput Accounting to guide adopters in selecting the agile practices with the potential for the greatest positive impact. This implies adopting practices one at a time.

That said, I want to avoid change fatigue, so I guide teams to adopt a small cluster of new agile practices at once, rather than one at a time. I still use Throughput Accounting and Discovering Bottlenecks to figure out where to focus the change.

Most importantly, you need to work with the people to learn what will help them improve. I believe the theory that states that, in order to sustain improvement over time, we must take on significant challenges that are barely within/almost beyond our grasp.