Breads on steel getting burnt

try reducing the temperature somewhat

"... but the timing for baking is right?"

1.  Right for what?  Stone, a thin sheet pan, or a thick steel? Are  bagel recipes designed for baking on thin metal pans, stones, or thick steels?  What did the recipe-maker intend, or have in mind,  and then test their recipe on?

2. what do commercial bakers bake bagels on?  stone, thin steel pans held via racks, or thick steel?

3. What are the decks of "deck ovens" made of?  Steel or stone?

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Part two:

"Burning the bottoms" can be a problem for baking bread in an iron dutch oven, too.  Maybe you can adapt solutions for that to bagels.  Here's what I've done to reduce burning/browning of the underside of round loaves in a cast iron dutch oven:

1. put parchment paper on the inside bottom of the dutch oven.
2. lightly sprinkle semolina or cornmeal under the parchment to create tiny air spaces that help insulate.
3. move the dutch oven to a higher position in the oven, so that it gets less "radiant" heat from the bottom heating element.  Radiant heat varies inversely to the square of the distance.
4. Put a cookie sheet, or other pan, or baking stone, or a sheet of aluminum foil, on the rack below the rack holding the dutch oven,  to "shade" the dutch oven from the radiant heat ("sunshine" heat) of the lower heating element.  Just like your car stays cooler in the shade than in the sun on a summer day.  "convection", transfer of heat via air, stays the same, but "radiant" is another thing.  Those bottom heating elements "radiate" just like the sun.

Hope this helps.  (And your bagels look great!  Love the multi-seeded ones.)

try reducing the temperature somewhat, ok, a lot.

The problem with steel is that it transfers heat right away and burns the bottoms before you can turn down the heat.  Take a frying pan for example.  Would you drop your pancakes in on high heat after the pan is super hot?  Or would you start just above medium and work up until you got nice insides and nice color?   

A stone on the other hand transfers heat differently and the recipe pictures look more like a stone. 

 My husband gave me a scrape of stainless steel once to use in my little mini oven in China.  Naturally the first thing I baked on it burned the bottom, just like frying too hot in a pan on the stove.  When I reduced the temp, I got better results.  You may find it takes longer to bake.    Check out temperatures for frying on the stove and compare.

While we're at it, a dark surface will heat up more than a shiny one.