It's incredible how little respect there is for political systems that incentivize stability.
Parliamentary republics do tend to form less stable governments, but it's also true that you can really govern by compromising both with your party, allies, and opposition.
In over 50 years not a single parliamentary republic has turned authoritarian, in fact only Sri Lanka in the 70s has done so since world war 2.
Presidential and semi-presidential republics? They are all just waiting for the right person at the right time, from Turkey to Nicaragua to the Philippines to Russia, etc, etc.
I don't think any modern country should aim at anything less than boring, albeit unstable, parliamentary republics, with presidents that are not elected by popular vote (like in Germany or Italy) and have no executive power.
If your country is doing good, you likely want minor/middle steer adjustements, not radical changes at each new vote.
Counterpoint when things aren't going well you may need major adjustments. For example The Civil War, the Great Depression etc.
> In over 50 years not a single parliamentary republic has turned authoritarian, in fact only Sri Lanka in the 70s has done so since world war 2.
Also I take issue with this stawnt as basically no Presidential Republic that had a functioning Presidential Republic prior to WW2 has gone authoritarian. What your pointing to has more to do with the overall legitimacy of governments themselves.
In addition your claim itself is false as we have plenty of parliamentary republics that devolve into authoritarian dictatorships including but not limited to - Mynamar - Nigeria - Ghana - Uganda - South Korea (Second Republic) - Syria - Pakistan experiencing various military coups.
I think it's the explicit lack of executive power that's the important part, not the lack of a direct popular vote. There doesn't seem to be much of a difference between say, the presidency of Finland (elected) and that of Estonia (appointed).
In fact, I'd say that Ireland's (directly elected) presidency has been one of the most notably successful, particularly in the post-1990 period when it's taken on more of a "cultural" rather than "political" focus.