Just a note if/when we return to this and apologies if this was already discussed but decided against: the editor-provided interlanguage links that override Wikidata are still part of articles and are extracted (alongside the Wikidata-maintained interlanguage links) in language-specific dump files. For English 2020-02-01, the file is named enwiki-20200201-langlinks.sql.gz and if you search for the page ID for Neoplasm (1236730), as follows, you get (with some cleaning up from my crude grep query), all of the Wikidata AND user-provided language links (in this case, German) out of the English article:

grep -o '(1236730,........................' ~/Downloads/enwiki-20200201-langlinks.sql
(1236730,'af','Gewas')
(1236730,'ar','ورم')
(1236730,'bn','নিওপ্লাজম')
(1236730,'ca','Neoplàsia')
(1236730,'cy','Tiwmor')
(1236730,'da','Neoplasi')
(1236730,'de','Neoplasie')
(1236730,'el','Νεόπλασμα')
(1236730,'es','Neoplasia')
(1236730,'et','Kasvaja')
(1236730,'eu','Neoplasia')
(1236730,'fa','نئوپلاسم')
(1236730,'fr','Néoplasie')
(1236730,'ga','Sceachaill')
(1236730,'gl','Neoplasia')
(1236730,'he','נאופלזיה')
(1236730,'hi','फुलाव')
(1236730,'hu','Neoplasia')
(1236730,'id','Neoplasma')
(1236730,'it','Neoplasia')
(1236730,'kn','ಗಂತಿ')
(1236730,'ko','신생물')
(1236730,'la','Neoplasma')
(1236730,'lt','Neoplazma')
(1236730,'ms','Neoplasma')
(1236730,'nl','Neoplasie')
(1236730,'nn','Neoplasi')
(1236730,'no','Neoplasi')
(1236730,'pl','Nowotwór')
(1236730,'pt','Neoplasma')
(1236730,'ro','Neoplasm')
(1236730,'sh','Neoplazma')
(1236730,'sr','Неоплазма')
(1236730,'sv','Neoplasi')
(1236730,'ta','கட்டி (உயிரியல்)')
(1236730,'th','เนื้องอก')
(1236730,'ur','نُفّاخ')
(1236730,'vi','Khối u')
(1236730,'zh','贅生物')

Cherry is much harder because no one has added the interlanguage links within the English article to indicate that the German article does exist but as a section under a slightly different topic. Uncovering missing interlanguage links like this though is very very difficult given all of the good work that has already been done by the editor community. That being said, the analogous example for spot welding, where the English article explicitly does link to article sections in German and Italian can also be recovered through the langlinks dump:

grep -o '(229103,....................' ~/Downloads/enwiki-20200201-langlinks.sql
(229103,'ar','لحام بقعة')
(229103,'ca','Soldadura per punts')
(229103,'de','Widerstandsschweißen#Widerstandspunkt- und Buckelschweißen')
(229103,'es','Soldadura por puntos')
(229103,'fa','جوشکاری نقطهای')
(229103,'he','ריתוך נקודות')
(229103,'it','Saldatura#Saldatura a punti')
(229103,'ja','スポット溶接')
(229103,'nl','Puntlassen')
(229103,'pt','Solda ponto')
(229103,'ro','Sudură în puncte')
(229103,'ru','Точечная контактная сварка')
(229103,'simple','Resistance welding')
(229103,'sv','Punktsvetsning')
(229103,'te','స్పాట్ వెల్డింగు')
(229103,'uk','Точкове зварювання')

Following up because I stumbled across a prior discussion of the solution I raise above (T203041#4640203). Looks like the tumor example was handled differently back then, so the langlinks solution had been considered but deemed insufficient.

We could also consider mining article / sub-article relationships to identify topics that are likely to be a section of a larger article prior to being a stand-alone article. This specifically would help cover the Cherry use-case. In the English article for Prunus avium, a species of cherry that is also linked via Wikidata to the German article on cherries, there's a link to the English Cherry article as a main article for more information. We might only recommend creating the article for Cherry in another language if that language neither has an article for Cherry nor Prunus avium. This might be overly restrictive but should remove a bunch of false positives hopefully.
More information: http://brenthecht.com/publications/cscw17_subarticles.pdf