In case we can't find a place to eat (which is nearly impossible in Osaka)

https://www.tsunagujapan.com/30-cheap-and-delicious-restaurants-in-osaka/

https://www.tsunagujapan.com/20-recommended-places-to-eat-in-dotonbori-osaka/

Hokkyoku: Homemade Ice Candy (北極) - 3 Chome-8-22 Nanba Chuo-ku, Osaka - https://hokkyoku.jp/

Takoyaki -

Everywhere, but these are well-known

Acchichi Honpo (Fresh Catch) - 7-19, Souemon-cho, Chuo-ku (Open Late 2am) - http://www.acchichi.com/
Aizuya (Origin of Takoyaki) - B1F, Namba Chikatetsu Nannan Town, 5-4-1, Namba, Chuo-ku - https://www.aiduya.com/
Takoyaki Juhachiban - 1F, Nakaza Kuidaore Bldg., 1-7-21, Dotonbori, Chuo-ku - https://d-sons18.co.jp/
Kougaryu - https://kougaryu.jp/shop/

Okonomiyaki

Mizuno - 1-4-15, Dotonbori, Chuo-ku, Osaka-shi, Osaka 大阪府大阪市中央区道頓堀1-4-15 -
https://tabelog.com/osaka/A2701/A270202/27001278/

Ramen

Kinryu Ramen - Dotonbori Branch - 1-7-26, Dotonbori, Chuo-ku, Osaka-shi, Osaka 大阪府大阪市中央区道頓堀1-7-26 - https://tabelog.com/osaka/A2701/A270202/27001495/

Tempura

Sakamachi no Ten-don LUNCH ONLY (until 2pm or runs out) - 1-8-16, Sennichimae, Chuo-ku, Osaka-shi, Osaka
https://tabelog.com/osaka/A2701/A270202/27001246/

Conveyor Belt Sushi

Kaitenzushi Chojiro Hozenji - 廻転寿司CHOJIRO 法善寺店

Daiki-suisan kaitenzushi Namba-walk - 大起水産 回転寿司 なんばウォーク店

Daiki-suisan kaitenzushi Dotombori - 大起水産 回転寿司 道頓堀店

Tekomai: All-You-Can-Eat-Steak - 4-16 Doyamacho Kita-ku, Osaka - http://298group.com/accessNamba.html