哈哈　我会说： 好好泡个澡 以及 修复网络连接 ；）

As MAKE & FIX are verbs with too many meanings and usages, let me focus on your examples. “Make the bath more comfortable” would be （probably 通过改装）让浴盆用起来更舒服。 "Fix the internet connection" would be 把网修/弄好。or 把网连上。 (BTW，弄 is a fits-all word, if you fix a problem, you 把它弄好。)

"Make" in Chinese always mean "let" or "do", your example means 更舒服地洗澡。The example of "fix" means 修理网络连接