In terms of the constant manager turnover my thoughts on it is we have the team to get result and we are already in the vicious cycle of manager turnover so why settle now? We could bite the bullet a bit longer and get the right manager for us and with Brands being in control of that decision I have all the faith that the next decision 1) won’t be made emotionally 2) will be chosen to get best out of the team positionally and 3) not cause months of controversy.
Managers with no previous managerial experience:
Nagelsmann - Hoffenheim - won 7/14 of the remaining games of his first season to stave off relegation, first full season in charge placed 4th and took Hoffenheim to their fist European competition in their long history.
Laurent Blanc - Bordeaux - In his first season he won manager of the year and a 2nd place finish in his first season as manager at Montpellier.
Roberto Mancini - Fiorentina/Lazio won the copa italia for Fiorentia his first year under extreme financial restraints to go as far as he sacrificed his pay so the players could be paid. Next year at Lazio got to the UEFA semifinals, 4th in the league, and won copa Italian again.
Pep - Barca - Was the manager of the youth team for only a couple months before taking over the first team winning the Treble in his first year.
These are just examples of managers in the top 5 for their first jobs. There are definitely others out there, just time consuming to search them all and remember the past ones. Also much more from lower leagues