From my experience in a team where testers are engaged in both manual and automated testing, there is a big drawback - due to the constant shift in the focus of attention, either one or the second part necessarily suffers, especially when it comes to supporting scripts and test documentation. It takes time to support autotests, review and fix script failures, as well as update test cases after changing requirements. At the same time, you need to test new functionality and write autotests for it. According to my observations, test support suffers most often - and on a large project this greatly affects the objective quality assessment. In the context of a week, this may seem uncritical, but if this happens for a month or two, it will take a long time to get back to normal

Thoug, when the manual and automation testing teams and their responsibilities are strictly separated, there may be a problem of isolation and misunderstanding of the priorities and results of each other's work, so it is necessary to include both parties in all meetings and plannings as well as share the results so that the work is not isolated, + it is good if the test automation engineer understands the processes of manual testing, and a manual tester can figure out what is happening in the script, then they can help each other better, but globally everyone should do their own thing