I want to add some suggestions here for making it easier on other parents in dire Snoo situations and don't want to have to splice anything. The critical part is knowing that you need a 7.9 mm x 5.5 mm barrel plug to fit into the bottom of the Snoo bassinet. I found one on Amazon that comes in a set of 38 different power supply adapters. It's called "aceyoon Laptop DC Power Adapter Kits 38 PCS Universal 5.5 mm x 2.1 mm DC AC Power Adapter Tips Connector for Lenovo Thinkpad Power Supply Plug Jack Sets" and has one day delivery.
Then you're going to need a general power supply. If you happen to be the type of person like me if it saves power supplies from old electronic devices that you've gotten rid of, you may already have what you need. Essentially you need to have a power supply that has 12V(volt) & minimum 2A (amp) output with a 5.5mm plug. A lot of laptops have this exact configuration. For example this "LEDMO Power Supply, Transformers,LED Adapter, 12V, 5A Max, 60 Watt Max, for LED Strip" which ships in one day from Amazon will totally work.
And yes, the amperage of the replacement power supply can exceed what the device being charged requires.
These two products combined worked for me (total price $25), and will for you as well. The official Snoo power supply delivered in 1 day would cost you $60.
So before you ever connect anything electrical (especially when connecting to a wall outlet) you must know the voltage that the device you are powering is rated for and what the input voltage is.
Since you probably have 120V AC coming out of your wall, connected to a 12V DC motor, it's no wonder that stuff explodes. So you have to step down the voltage to the specified voltage on the motor. You can use some kind of adapter that converts it properly (like a phone charger, it will say the output voltage on the side). Then put the switch and the lamp before the conversion and the motor after. I'm no expert though
I've been using this power supply for two 16ft light strips that are connected to one controller and it's been working good. LEDMO Power Supply, Transformers,LED Adapter, 12V, 5A Max, 60 Watt Max, for LED Strip https://www.amazon.com/dp/B01461MOGQ/ref=cm_sw_r_cp_apa_i_9YTRDb5S1HY57
The HLG does not include a PS, but the MARS does.
None of the various types of diodes absolutely require a constant current PS. Constant current sources just give the diodes the longest lifetime at peak illumination. Here's a guide to choosing a constant voltage driver for COBs.
The power supply would absolutely not double the price.
Like I said, the amazon recommended PS is $11. More than the cost of your linked 5054 strip light.
You can certainly buy (or build) your own switching PS for a lot cheaper. No guarantees on the efficiency, though.
I personally use blade server power supplies, but they require a lot of trial and error to get working. High efficiency, reliability, and lifetime. They can get heavy though.
One assumption in your calculation is that all 50W is going to the diodes. It looks like the linked product uses current limiting resistors. It's the cheapest way to limit current, but it's a lot of wasted power... and there's no way to get around them.
LEDMO Power Supply, Transformers,LED Adapter, 12V, 5A Max, 60 Watt Max, for LED Strip https://www.amazon.com/dp/B01461MOGQ/ref=cm_sw_r_cp_api_glt_fabc_Q3Z0KHMQ4N6ZP9C6NAGX?_encoding=UTF8&psc=1 I have this one as my back up when the original one showed up broken for my wheel.