First of all, not all but most of the answers you have received are based in psychological inertia, loss aversion, confirmation bias, availability cascade and shoehorning of scenarios, and so they are subjective, poor and based in government sponsored petrochemical industry ICE piston or jet engine obsolete technology, that has hijacked aviation technology for so long with inefficient aerodynamics and propulsion systems, that in this case has limitation in propulsion placement because of the whirl created by all those engines's moving pieces and other factors (the unlikes of this post prove that fundamentalism that has nothing to do with aviation, technology or science, but with fake technology advocacy that avoids and tries to suppress any challenge to the technological status quo. as today there have been 3 or 4 unlikes that have countered the 2 or 3 likes of this answer and keep this answer as negative. this type of behaviour is a plage in several pseudo technological aviation or boat design forums created by biased people hoping for advertising revenue or even wiki pages, which i do not recommend to enter).
With other types of propulsion as battery electric, hydrogen electric, solar electric, solar stirling or isothermal compressed air ICA propulsion ( https://www.reddit.com/r/AerospaceEngineering/comments/pkmdz6/stable_flying_wing_design_setup_propelled_by/ ) there are no barriers to propulsion placement and so there can be several configurations as distributed electric propulsion DEP with boundary layer suction or ingestion and wing tip propellers as nasa x-57 (https://www.nasa.gov/aeroresearch/X-57/technical/index.html) and other publications (https://www.researchgate.net/publication/329036195_Wingtip-Mounted_Propellers_Aerodynamic_Analysis_of_Interaction_Effects_and_Comparison_with_Conventional_Layout).
Rather than a simplification or eliminating discourse of centre propeller vs wing tip propellers, they can be a complement for the main aircraft propulsion and can play a role in swept angle tailless aircrafts by moving part of the propulsion further aft (tailless aircrafts normally use push propulsion for that effect), which are far more efficient that today's petrol aircrafts with cylindrical fuselage and short aspect ratio wings.
Wing tip propellers can increase lift that is very important for STOL development, thrust and reduce induced drag by rotating counterwise to the wingtip vortex (nasa x-57) and they can increase stability of the aircraft by placing them off-axis (NEW EDIT: this is the real publication: Wingtip-mounted propellers installed at a nonzero yaw angle 2021 Thesis of Yannick Chance https://repository.tudelft.nl/islandora/object/uuid:7aceebd5-4221-41f0-8657-3b61b152cad0) what can open the door to fly-by-wire 3d gyrating or 2d rotating wing tips propellers as stability assistance during adverse weather conditions instead spoilers or ailerons, what can increase also roll rate and manoeuvrability.
Also in the case of general aviation aircrafts, by being placed in the tips the propellers create less parasitical drag compared to a pull centre propeller that creates additional turbulences and parasitical drag trough all the fuselage, a drag rate that increases exponentially with the speed.
As propellers and propeller arrays have several uses as take-off thrust, climbing or soaring thrust, cruising thrust or gliding assistance thrust, in the end wing tips propellers can help to reduce drag of sailplanes at small rpm or reduce drag during cruising in different aircrafts with additional thrust, besides increasing the mentioned directional stability of aircrafts and improve STOL performance.
there are several trade-offs of wing-tip propulsion, and it will vary by the type of propeller or engine and also from aircrafts with only wing tip propulsion to with aircrafts that use additional propulsion besides wing tip propulsion, and also from tailless aircrafts to tailplanes, and push or pull configurations, and cruising speed as well:
-As with DEP there is wing and whirl flutter and so the need of additional structural reinforcement, however the weight and whirl of electric motors are a small percentage of a combustion engine and even less in the case of pistonless rotary air engines, and also flutter can be further reduced by using a small or partial percentage of the total aircraft thrust in the wing tips.
-Width increase and propeller crash on landing can be a problem by using fixed propellers, however as today there are propellers that can be folded so this issue can be totally avoided.
-single engine failure will be a problem in aircrafts that only use wing tip propulsion, and compared to twin engine aircrafts because it still will be an advantage compared to an engine failure in general aviation single ICE engine aircrafts.
-yaw and roll performance in the case of aircrafts using only wing tip fixed axis propulsion, however an aircraft that uses gyrating or rotating propellers in the wing tips will have better yaw and roll performance than today's single or twin propeller tailplanes that depend from spoilers, alieron and rudder besides having a greater stability control, and for tailless aircrafts this means a gamechanging technology that is currently in development or to be developed.