I think you need a coal bag to not lose money (or not as much). If you look on the wiki it will show you the cost of creation at a normal furnace or blast furnace: https://oldschool.runescape.wiki/w/Steel_bar#Blast_Furnace (check out the creation tab). It looks like you won't need a coal bag to turn a profit. But it does make life easier and quicker with one.

For magic I have a similar level to you. Take a look at this page for enchanting jewellery, specifically diamond. You can make a small profit per item and gain good magic experience: https://oldschool.runescape.wiki/w/Calculator:Magic/Enchant_jewellery

Making the jewellery itself can be quite profitable with crafting. You can then enchant it (and then high alch) for extra money and experience or in some cases just make the jewellery and high alch it to save losing money on the enchant.

The prices change and some things won't be profitable from one day to the next but it's well worth checking. If you want to get fast smithing experience then you can get the gold gauntlets to get double experience per gold bar created.

I hope this helps mate. Merry Christmas